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Dissertations / Theses on the topic 'Gas turbine'

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Published: 4 June 2021
Last updated: 11 September 2023

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1

Ozmen, Teoman. "Gas Turbine Monitoring System." Master's thesis, METU, 2006. http://etd.lib.metu.edu.tr/upload/12607957/index.pdf.

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In this study, a new gas turbine monitoring system being able to carry out appropriate run process is set up for a gas turbine with 250 kW power rating and its accessories. The system with the mechanical and electrical connections of the required sub-parts is transformed to a kind of the test stand. Performance test result calculation method is described. In addition that, performance evaluation software being able to apply with the completion of the preliminary performance tests is developed for this gas turbine. This system has infrastructure for the gas turbine sub-components performance and aerothermodynamics research. This system is also designed for aviation training facility as a training material for the gas turbine start and run demonstration. This system provides the preliminary gas turbine performance research requirements in the laboratory environment.
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2

Flesland, Synnøve Mangerud. "Gas Turbine Optimum Operation." Thesis, Norges teknisk-naturvitenskapelige universitet, Institutt for energi- og prosessteknikk, 2010. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-12409.

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Many offshore installations are dependent on power generated by gas turbines and a critical issue is that these experience performance deterioration over time. Performance deterioration causes reduced plant efficiency and power output as well as increased environmental emissions. It is therefore of highest importance to detect and control recoverable losses in order to reduce their effect. This thesis project was therefore initiated to evaluate parameters for detecting performance deterioration in addition to document different aspects of gas turbine degradation and performance recovery. Compressor fouling is the largest contributor to performance deterioration. Investigating fouling was therefore the main focus of this study.In the present study the deterioration rates of four different gas turbines were evaluated. When choosing gas turbines it was emphasised to select gas turbines operating under equal conditions but with different washing procedures. In addition to offline washing two of the gas turbines had daily online washing routines and one of the gas turbines run idle wash every 1000 hour between each offline wash. Data was extracted from the monitoring software, TurboWatch, and loaded into Excel files. MATLAB scripts were created to handle the large amount of data and visualize performance trends. Series of two parameters were plotted against each other and the graphs were evaluated.The evaluation showed that an overall trend was that the gas turbine that had been running with online washing continuously over a long period of time had higher performance than the reference engine. For the second gas turbine a daily online washing procedure has recently started. The advantage with the evaluation of this gas turbine was that a good reference engine was available. The two engines were operating under quite similar conditions at the same location in addition to having equal filter systems. Some deterioration trends were possible to detect. For the first period both engines seemed to have quite equal deterioration trends. During the second period no clear trends were seen in corrected CDP and corrected EGT when evaluated for constant GG speed. The compressor efficiency had decreasing trends for both engines during the second period as well, but the compressor efficiency for machine 1 was overall higher during the period with online washing than the previous period. The borescope pictures taken after the first period with online washing showed good visual results. However, it is too premature to make a final decision regarding the exact performance gain of online washing. At the time the study was performed the engine had only been running online washing for one operating interval, and more investigation over longer time is recommended. For the engine running with idle wash it was not possible to conclude on the basis of the collected data. No clear deterioration trends were detected and investigations over longer time and several operating intervals are recommended. It is also important to be aware of the fact that the performance gain of idle wash needs to be much higher than for online washing in order for idle wash to be economically profitable. There are several uncertainties related to performance trends. These include inaccuracy in instrumentation, monitoring software, calibration etc. Due to the fact that all the gas turbines evaluated in this study only have standard instrumentation it caused additional uncertainty in the performance trends. One suggestion for further study is to initiate a test instrumented gas turbine into operation with sensors for measuring inlet pressure depression
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3

Spencer, Matthew Richard. "Gas turbine lubricant evaluation." Thesis, University of Birmingham, 2014. http://etheses.bham.ac.uk//id/eprint/5423/.

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This thesis is a study of the chemical and physical changes which can occur to gas turbine lubricants as a result of exposure to operational conditions. The continual evolution toward more efficient gas turbines is accompanied by increasing thermal and mechanical loading which the lubricant must be able to withstand. In this thesis two major degradation issues are studied; thermal oxidative degradation and lubricant deposition. In the area of thermal oxidative degradation, efforts are made to better understand the key parameters which determine the lubricant breakdown mechanism. Through control of these parameters and comparison to service derived gas turbine oil samples a new laboratory methodology is proposed for the assessment of lubricant oxidative degradation. The study of lubricant deposition in this thesis is concentrated on the regions of highest risk, the bearing chamber feed (single phase) and vent (two phase) oil pipes. Development of existing laboratory scale deposition simulators was conducted to increase how engine representative the methods are of gas turbine conditions. These simulators were used to evaluate the rate of deposition with a range of lubricants, simulated engine cycles and pipe surfaces.
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4

Rice, Matthew Jason. "Simulation of Isothermal Combustion in Gas Turbines." Thesis, Virginia Tech, 2004. http://hdl.handle.net/10919/9723.

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Current improvements in gas turbine engine performance have arisen primarily due to increases in turbine inlet temperature and compressor pressure ratios. However, a maximum possible turbine inlet temperature exits in the form of the adiabatic combustion temperature of the fuel. In addition, thermal limits of turbine blade materials also places an upper bound on turbine inlet temperatures. Thus, the current strategy for improving gas turbine efficiency is inherently limited. Introduction of a new gas turbine, based on an alternative work cycle utilizing isothermal combustion (i.e. combustion within the turbine) affords significant opportunities for improving engine output and/or efficiency. However, implementation of such a scheme presents a number of technological challenges such as holding a flame in high-speed flow. The current research is aimed at determining whether such a combustion scheme is feasible using computational methods. The geometry, a simple 2-D cascade utilizes surface injection within the stator or rotor boundary layers (including the rotor pressure side recirculation zone (a natural flame holder). Computational methods utilized both steady and time accurate calculations with transitional flow as well as laminar and turbulent combustion and species transport. It has been determined that burning within a turbine is possible given a variety of injection schemes using "typical" foil geometries under "typical" operating conditions. Specifically, results indicate that combustion is self-igniting and, hence, self-sustaining given the high temperatures and pressures within a high pressure turbine passage. Deterioration of aerodynamic performance is not pronounced regardless of injection scheme. However, increased thermal loading in the form of higher adiabatic surface temperatures or heat transfer is significant given the injection and burning of the fuel within the boundary layer. This increase in thermal loading is, however, minimized when injection takes place in or near a recirculation zone. The effect of injection location on pattern factors indicates that suction side injection minimizes temperature variation downstream of the injection surface (for rotor injection only). In addition, the most uniform temperature profile (in the flow direction) is achieved by injection fuel and combustion nearest to the source of work extraction. Namely, injection at the rotor produces the most "isothermal" temperature distribution. Finally, a pseudo direct simulation of an isothermal machine is conducted by combining simulation data and assumed processes. The results indicate that isothermal combustion results in an increase in turbine specific work and efficiency over the equivalent Brayton cycle.
Master of Science
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5

Bartlett, Michael. "Developing Humidified Gas Turbine Cycles." Doctoral thesis, KTH, Chemical Engineering and Technology, 2002. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3437.

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As a result of their unique heat recovery properties,Humidified Gas Turbine (HGT) cycles have the potential todeliver resource-effective energy to society. The EvaporativeGas Turbine (EvGT) Consortium in Sweden has been studying thesetypes of cycles for nearly a decade, but now stands at acrossroads, with commercial demonstration remaining. Thisthesis binds together several key elements for the developmentof humidified gas turbines: water recovery and air and waterquality in the cycle, cycle selection for near-term, mid-sizedpower generation, and identifying a feasible niche market fordemonstration and market penetration. Moreover, possiblesocio-technical hinders for humidified gas turbine developmentare examined.

Through modelling saltcontaminant flows in the cycle andverifying the results in the pilot plant, it was found thathumidification tower operation need not endanger the hot gaspath. Moreover, sufficient condensate can be condensed to meetfeed water demands. Air filters were found to be essential tolower the base level of contaminant in the cycle. This protectsboth the air and water stream components. By capturing airparticles of a similar size to the air filters, the humidifieractually lowers air stream salt levels. Measures to minimisedroplet entrainment were successful (50 mg droplets/kg air) andmodels predict a 1% blow down from the water circuit issufficient. The condensate is very clean, with less than 1 mg/lalkali salts and easily deionised.

Based on a core engine parameter analysis for three HGTcycle configurations and a subsequent economic study, asteam-cooled steam injected cycle complemented with part-flowhumidification is recommended for the mid-size power market.This cycle was found to be particularly efficient at highpressures and turbine inlet temperatures, conditions eased bysteam cooling and even intercooling. The recommended HGT cyclegives specific investment costs 30- 35% lower than the combinedcycles and cost of electricity levels were 10-18% lower.Full-flow intercooled EvGT cycles give high performances, butseem to be penalised by the recuperator costs, while stillbeing cheaper than the CC. District heating is suggested as asuitable niche market to commercially demonstrate the HGTcycle. Here, the advantages of HGT are especially pronounceddue their very high total efficiencies. Feasibility prices forelectricity were up to 35% lower than competing combinedcycles. HGT cycles were also found to effectively include wasteheat sources.

Keywords:gas turbines, evaporative gas turbines,humidification, power generation, combined heat and powergeneration.

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6

Pachidis, Vassilios A. "Gas turbine advanced performance simulation." Thesis, Cranfield University, 2006. http://dspace.lib.cranfield.ac.uk/handle/1826/4529.

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Current commercial 'state of the art' engine simulation software is of a low fidelity. Individual component performance characteristics are typically represented via nondimensional maps with empirical adjustments for off-design effects. Component nondimensional characteristics are usually obtained through the averaging of experimental readings from rig test analyses carried out under nominal operating conditions. In those cases where actual component characteristics are not available and default maps are used instead, conventional simulation tools can offer a good prediction of the performance of the whole engine close to design point, but can deviate substantially at of design and transient conditions. On the other hand, even when real component characteristics are available, zero-dimensional engine cycle simulation tools can not predict the performance of the engine at other than nominal conditions satisfactorily. Low-fidelity simulation tools are generally incapable of analyzing the performance of individual engine components in detail, or capturing complex physical phenomena such as inlet flow distortion. Although the available computational power has increased exponentially over the last two decades, a detailed, three-dimensional analysis of an entire propulsion system still seems to be so complex and computationally intensive as to remain cost-prohibitive. For this reason, alternative methods of integrating different types and levels of analysis are necessary. The integration of simulation codes that model at different levels of fidelity into a single simulation provides the opportunity to reduce the overall computing resource needed, while retaining the desired level of analysis in specific engine components. The objective of this work was to investigate different simulation strategies for communicating the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to an engine system analysis carried out at a lower level of resolution. This would allow component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. More specifically, this work identified and thoroughly investigated several advanced simulation strategies in terms of their actual implementation and potential, by looking into relative changes in engine performance after integrating into the basic, nondimensional cycle analysis, the performance characteristics of i) two-dimensional Streamline Curvature (SLC) and ii) three-dimensional Computational Fluid Dynamics (CFD), engine component models. In the context of this work, several case studies were carried out, utilising different two-dimensional and three-dimensional component geometries, under different operating conditions, such as different types and extents of compressor inlet pressure distortion and turbine inlet temperature distortion. More importantly, this research effort established the necessary methodology and technology required for a full, twodimensional engine cycle analysis at an affordable computational resource.
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7

Pachidis, Vassilios. "Gas Turbine Advanced Performance Simulation." Thesis, Cranfield University, 2006. http://hdl.handle.net/1826/4529.

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Current commercial `state of the art' engine simulation software is of a low fidelity. Individual component performance characteristics are typically represented via nondimensional maps with empirical adjustments for off-design effects. Component nondimensional characteristics are usually obtained through the averaging of experimental readings from rig test analyses carried out under nominal operating conditions. In those cases where actual component characteristics are not available and default maps are used instead, conventional simulation tools can offer a good prediction of the performance of the whole engine close to design point, but can deviate substantially at of design and transient conditions. On the other hand, even when real component characteristics are available, zero-dimensional engine cycle simulation tools can not predict the performance of the engine at other than nominal conditions satisfactorily. Low-fidelity simulation tools are generally incapable of analyzing the performance of individual engine components in detail, or capturing complex physical phenomena such as inlet flow distortion. Although the available computational power has increased exponentially over the last two decades, a detailed, three-dimensional analysis of an entire propulsion system still seems to be so complex and computationally intensive as to remain cost-prohibitive. For this reason, alternative methods of integrating different types and levels of analysis are necessary. The integration of simulation codes that model at different levels of fidelity into a single simulation provides the opportunity to reduce the overall computing resource needed, while retaining the desired level of analysis in specific engine components. The objective of this work was to investigate different simulation strategies for communicating the performance characteristics of an isolated gas turbine engine component, resolved from a detailed, high-fidelity analysis, to an engine system analysis carried out at a lower level of resolution. This would allow component-level, complex physical processes to be captured and analyzed in the context of the whole engine performance, at an affordable computing resource and time. More specifically, this work identified and thoroughly investigated several advanced simulation strategies in terms of their actual implementation and potential, by looking into relative changes in engine performance after integrating into the basic, nondimensional cycle analysis, the performance characteristics of i) two-dimensional Streamline Curvature (SLC) and ii) three-dimensional Computational Fluid Dynamics (CFD), engine component models. In the context of this work, several case studies were carried out, utilising different two-dimensional and three-dimensional component geometries, under different operating conditions, such as different types and extents of compressor inlet pressure distortion and turbine inlet temperature distortion. More importantly, this research effort established the necessary methodology and technology required for a full, twodimensional engine cycle analysis at an affordable computational resource.
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8

Spencer, A. "Gas turbine combustor port flows." Thesis, Loughborough University, 1998. https://dspace.lboro.ac.uk/2134/6883.

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Competitive pressure and stringent emissions legislation have placed an urgent demand on research to improve our understanding of the gas turbine combustor flow field. Flow through the air admission ports of a combustor plays an essential role in determining the internal flow patterns on which many features of combustor performance depend. This thesis explains how a combination of experimental and computational research has helped improve our understanding, and ability to predict, the flow characteristics of jets entering a combustor. The experiments focused on a simplified generic geometry of a combustor port system. Two concentric tubes, with ports introduced into the inner tube's wall, allowed a set of radially impinging jets to be formed within the inner tube. By investigating the flow with LDA instrumentation and flow visualisation methods a quantitative and qualitative picture of the mean and turbulent flow fields has been constructed. Data were collected from the annulus, port and core regions. These data provide suitable validation information for computational models, allow improved understanding of the detailed flow physics and provide the global performance parameters used traditionally by combustor designers. Computational work focused on improving the port representation within CFD models. This work looked at the effect of increasing the grid refinement, and improving the geometrical representation of the port. The desire to model realistic port features led to the development of a stand-alone port modelling module. Comparing calculations of plain-circular ports to those for more realistic chuted port geometry, for example, showed that isothermal modelling methods were able to predict the expected changes to the global parameters measured. Moreover, these effects are seen to have significant consequences on the predicted combustor core flow field.
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9

Ahmad, N. T. "Swirl stabilised gas turbine combustion." Thesis, University of Leeds, 1986. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.356423.

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10

Pishva, S. M. R. (S Mohammed Reza) Carleton University Dissertation Engineering Mechanical. "Rejuvenation of gas turbine discs." Ottawa, 1988.

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11

Asere, Abraham Awolola. "Gas turbine combustor wall cooling." Thesis, University of Leeds, 1986. http://etheses.whiterose.ac.uk/2590/.

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The need for better methods of cooling gas turbine combustors and a review of current cooling techniques have been presented. Three cooling methods are investigated: (a) Full Coverage Discrete Hole Film Cooling (Effusion), (b) Impingement/Effusion Hybrid Cooling Systems, and (c) Transpiration Cooling. The aim of these cooling techniques is to effectively and efficiently cool gas turbine combustors with a significant reduction in current cooling air requirements. The range of test conditions were coolant temperature, Tc, of 289 < Tc 710 K and combustion gases temperature, Tg, of 500 Tg N< 1900 K. The discharge coefficients of the effusion and the impingement/effusion systemshave also been studied. A detailed analysis has been made of the heat transfer of the cooling systems, jet penetration into the cross-stream, prediction of the cooling jet temperatures at various stages in the cooling process and the cooling film heat transfer coefficient. The results of the discharge coefficient (Cd) indicate a decreasing C with increasing wall thickness to diameter ratio, t/D, and a weak effect of cross-stream flow. The results of both the effusion and the impingement/effusion hybrid systems indicate a high cooling performance of similar magnitude to that of the transpiration system. Graphical design correlations for the cooling wall have been made. The optimum hole geometries for both cooling configurations have been developed. The influence of the coolant to hot gas density ratio has been studied over the range 1.4-3.4. In the design of effusion and impingement/effusion cooling systems, wall thickness, hole density, hole diameter and wall design pressure loss are significant parameters for cooling performance maximisation.
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12

Aslanidou, Ioanna. "Combustor and turbine aerothermal interactions in gas turbines with can combustors." Thesis, University of Oxford, 2015. https://ora.ox.ac.uk/objects/uuid:b1527fd0-8e54-4831-8625-32722141511e.

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As the research into the improvement of gas turbine performance progresses, the combustor-turbine interface becomes of increasing importance. In new engine designs components come closer together and the study of the combustor and turbine interactions can prove to be valuable for the improvement of the aerothermal performance of the vane. This thesis presents an experimental and numerical investigation of the aerodynamic and heat transfer aspect of the interactions between the combustor and the nozzle guide vane. In the gas turbine studied the trailing edge of the combustor transition duct wall is found upstream of every second vane. In the experimental measurements carried out in a purpose-built high speed experimental facility, the wake of this wall is shown to increase the aerodynamic loss of the vane. On the other hand, the wall alters secondary flow structures and has a protective effect on the heat transfer in the leading edge-endwall junction, a region that has proven to be detrimental to component life. The effect of different clocking positions of the vane relative to the combustor wall are tested experimentally and shown to alter the aerodynamic field and the heat transfer to the vane. The experimental methods and processing techniques adopted in this work are utilized to highlight the differences between the different cases studied. A new concept of using the combustor wall to shield the nozzle guide vane leading edge is introduced, followed by a proposed design that is numerically analysed, including a new cooling system. This uses continuous cooling slots on the upstream combustor wall to cool the vane leading edge. Coolant to the endwalls is provided from continuous slots on the combustor-turbine interface. The reduction of secondary flow through the removal of the horseshoe vortex in the new design results in improved cooling of the endwalls, with a higher average adiabatic effectiveness than in the original case, using the same coolant mass flow rate. The vane surface and suction side are also successfully cooled using less air than that required for a showerhead. The new vane is tested in the experimental facility. The improved aerodynamic and thermal performance of the shielded vane is demonstrated under engine-representative inlet conditions. The new design is shown to have a lower average total pressure loss than the original vane for all inlet conditions. The heat transfer on the vane surface is overall reduced for all inlet conditions and the peak heat transfer on the vane leading edge-endwall junction is moved further upstream, to a region that can be effectively cooled from the upstream cooling slots on the combustor wall trailing edge and the endwalls.
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Crosby, Jared M. "Particle Size, Gas Temperature, and Impingement Cooling Effects on High Pressure Turbine Deposition in Land Based Gas Turbines from Various Synfuels." Diss., CLICK HERE for online access, 2007. http://contentdm.lib.byu.edu/ETD/image/etd1774.pdf.

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14

Løver, Kristian Aase. "Biomass gasification integration in recuperative gas turbine cycles and recuperative fuel cell integrated gas turbine cycles : -." Thesis, Norwegian University of Science and Technology, Department of Energy and Process Engineering, 2007. http://urn.kb.se/resolve?urn=urn:nbn:no:ntnu:diva-9658.

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A multi-reactor, multi-temperature, waste-heat driven biomass thermochemical converter is proposed and simulated in the process simulation tool Aspen Plus™. The thermochemical converter is in Aspen Plus™ integrated with a gas turbine power cycle and a combined fuel cell/gas turbine power cycle. Both power cycles are recuperative, and supply the thermochemical converter with waste heat. For result comparison, the power cycles are also integrated with a reference conventional single-reactor thermochemical converter, utilizing partial oxidation to drive the conversion process. Exergy analysis is used for assessment of the simulation results. In stand-alone simulation, the proposed thermochemical shows high performance. Cold gas efficiency is 108.0% and syngas HHV is 14.5 MJ/kg on dry basis. When integrated with the gas turbine power cycle, the proposed converter fails to improve thermal efficiency of the integrated cycle significantly, compared to reference converter. Thermal efficiency is 41.8% and 40.7%, on a biomass HHV basis, with the proposed and the reference converter respectively. This is despite superior cold gas efficiency for the proposed converter, and the gas turbine cycle is found not to be able to properly take advantage of the high chemical energy in the syngas of the proposed converter. When integrated with the combined fuel cell/gas turbine power cycle, the proposed converter significantly improves the thermal efficiency of the integrated cycle, compared to the reference converter. Thermal efficiency is 56.0% and 51.2%, on a biomass HHV basis, with the proposed and the reference converter respectively. The fuel cell is found to be able to take advantage of the high chemical energy in the syngas of the proposed converter, which is the main cause of increase in thermal efficiency. Operation of the proposed thermochemical converter is found to be feasible at a wide range of operating conditions, although low operating temperatures in the converter may cause problems at very high carbon conversion ratios.

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Eskner, Mats. "Mechanical Behaviour of Gas Turbine Coatings." Doctoral thesis, KTH, Materials Science and Engineering, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3776.

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Coatings are frequently applied on gas turbine components inorder to restrict surface degradation such as corrosion andoxidation of the structural material or to thermally insulatethe structural material against the hot environment, therebyincreasing the efficiency of the turbine. However, in order toobtain accurate lifetime expectancies and performance of thecoatings system it is necessary to have a reliableunderstanding of the mechanical properties and failuremechanisms of the coatings.

In this thesis, mechanical and fracture behaviour have beenstudied for a NiAl coating applied by a pack cementationprocess, an air-plasma sprayed NiCoCrAlY bondcoat, a vacuumplasma-sprayed NiCrAlY bondcoat and an air plasma-sprayed ZrO2+ 6-8 % Y2O3topcoat. The mechanical tests were carried out ata temperature interval between room temperature and 860oC.Small punch tests and spherical indentation were the testmethods applied for this purpose, in which existing bending andindentation theory were adopted for interpretation of the testresults. Efforts were made to validate the test methods toensure their relevance for coating property measurements. Itwas found that the combination of these two methods givescapability to predict the temperature dependence of severalrelevant mechanical properties of gas turbine coatings, forexample the hardness, elastic modulus, yield strength, fracturestrength, flow stress-strain behaviour and ductility.Furthermore, the plasma-sprayed coatings were tested in bothas-coated and heat-treated condition, which revealedsignificant difference in properties. Microstructuralexamination of the bondcoats showed that oxidation with loss ofaluminium plays an important role in the coating degradationand for the property changes in the coatings.

Keywords:small punch test, miniaturised disc bendingtests, spherical indentation, coatings, NiAl, APS-NiCoCrAlY,VPS-NiCrAlY, mechanical properties

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Cavaliere, Davide Egidio. "Blow-off in gas turbine combustors." Thesis, University of Cambridge, 2014. https://www.repository.cam.ac.uk/handle/1810/265575.

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This thesis describes an experimental investigation of the flame structure close to the extinction and the blow-off events of non-premixed and spray flames stabilized on an axisymmetric bluff body in a confined swirl configuration. The comparison of flames of different canonical types in the same basic aerodynamic field allows insights on the relative blow-off behaviour. The first part of the thesis describes several velocity measurements in non-reacting and reacting flows. The main usefulness of this data is to provide the aerodynamic flow pattern and some discussion on the velocity field and the related recirculation zones. The velocity and turbulence information obtained are particularly useful for providing data, which is crucial for validation of computational models. The second part describes an experimental investigation of non-premixed stable flames very close to the blow-off condition. The measurements included visualisation of the blow-off transient with 5 kHz OH* chemiluminescence, which allowed a quantification of the average duration of the blow-off transient. OH-PLIF images at 5 kHz for flames far from and close to extinction showed that the non-premixed flame intermittently lifts-off the bluff body, with increasing probability as the fuel velocity increases. The flame sheet shows evidence of localised extinctions, which are more pronounced as approaching blow-off. The measurements include blow-off limits and their attempted correlation. It was found that a correlation based on a Damkohler number does a reasonable job at collapsing the dataset. The final part examines the blow-off behaviour of swirling spray flames for two different fuels: n-heptane and n-decane. The measurements include blow-off limits and their att~mpted correlation, visualisation of the blow-off transient with 5 kHz OH* chemiluminescence, and the quantification of the average duration of the blow-off transient. It was found that the average duration of the blow-off event is in order of the tens of ms for both spray flames (10-16 ms). The blow-off event is therefore a relatively slow process for the spray ~ames using n-heptane and decane fuels. This suggests that control measures, such as fast fuel injection, coupled with appropriate detection, such as with chemiluminescence monitoring, may have a reasonable chance of success in keeping the flame alight very close to the blow-off limit. These results, together with those obtained for the non-premixed gaseous case form a wide body of experimental data available for the validation of turbulent flame models. The quantification of some properties during the blow-off transient can assist studies of extinction based on large-eddy simulation that have a promise of capturing combustion transients.
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Bengtsson, Karl. "ThermoacousticInstabilities in a Gas Turbine Combustor." Thesis, KTH, MWL Marcus Wallenberg Laboratoriet, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-226530.

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Stationary gas turbines are widely used today for power generation and mechanical drive applications. The introduction of new regulations on emissions in the last decades have led to extensive development and new technologies used within modern gas turbines. The majority of the gas turbines sold today have a so called DLE (Dry Low Emission) combustion system that mainly operates in the leanpremixed combustion regime. The lean-premixed regime is characterized by low emission capabilities but are more likely to exhibit stability issues compared to traditional non-premixed combustion systems. Thermoacoustic instabilities are a highly unwanted phenomena characterized by an interaction between an acoustic eld and a combustion process. This interaction may lead to self-sustained large amplitude oscillations which can cause severe structural damage to the gas turbine if it couples with a structural mode. However, since a coupled phenomena, prediction of thermoacoustic stability is a complex topic still under research. In this work, the mechanisms responsible for thermoacoustic instabilities are described and a 1- dimensional stability modelling approach is applied to the Siemens SGT-750 combustion system. The complete combustor is modelled by so called acoustic two-port elements in which a 1-dimensional ame model is incorporated. The simulations is done using a generalized network code developed by Siemens. The SGT-750 shows today excellent stability and combustion performance but a deeper knowledge in the thermoacoustic behaviour is highly valued for future development. In addition, measurement data from an engine test is evaluated, post-processed and compared with the results from the 1-dimensional network model. The results are found to be in good agreement and the thermoacoustic response of the SGT-750 is found to be dominated by both global modes including all cans as well as local modes within the individual cans.
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Murthy, J. N. "Gas turbine combustor modelling for design." Thesis, Cranfield University, 1988. http://hdl.handle.net/1826/2626.

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The design and development of gas turbine combustors is a crucial but uncertain part of an engine development process. Combustion within a gas turbine is a complex interaction of, among other things, fluid dynamics, heat and mass transfer and chemical kinetics. At present, the design process relies upon a wealth of experimental data and correlations. The proper use of this information requires experienced combustion engineers and even for them the design process is very time consuming. Some major engine manufacturers have attempted to address the above problem by developing one dimensional computer programs based on the above test and empirical data to assist combustor designers. Such programs are usually proprietary. The present work, based on this approach has yielded DEPTH, a combustor design program. DEPTH ( Design and Evaluation of Pressure, Temperature and Heat transfer in combustors) is developed in Fortran-77 to assist in preliminary design and evaluation of conventional gas turbine combustion chambers. DEPTH can be used to carry out a preliminary design along with prediction of the cooling slots for a given metal temperature limit or to evaluate heat transfer and temperatures for an existing combustion chamber. Analysis of performance parameters such as efficiency, stability and NOx based on stirred reactor theories is also coupled. DEPTH is made sufficiently interactive/user-friendly such that no prior expertise is required as far as computer operation is concerned. The range of variables such as operating conditions, geometry, hardware, fuel type can all be effectively examined and their contribution towards the combustor performance studied. Such comprehensive study should provide ample opportunity for the designer to make the right decisions. It should also be an effective study aid. Returns in terms of higher thermal efficiencies is an incentive to go for combined cycles and cogeneration. In such cases, opting for higher cycle pressures together with a second or reheat combustor promise higher thermal efficiencies and exhaust temperatures and hence such designs are likely to be of interest. The concepts that are needed for understanding a double or reheat combustor are also addressed using the programme. A specific application of the programme is demonstrated through the design of a double combustor.
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Ismail, Ibrahim H. "Simulation of aircraft gas turbine engine." Thesis, University of Hertfordshire, 1991. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.303465.

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Farahani, Arash. "Gas turbine engine static strip seals." Thesis, University of Sussex, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.444118.

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21

Andrews, G. E. "Gas turbine combustion with low emissions." Thesis, University of Leeds, 1989. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.329381.

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22

Abdul, Husein Reyad Abdul Ameer. "Impingement cooling of gas turbine components." Thesis, University of Leeds, 1990. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.255236.

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23

ASSUMPCAO, VICTOR DOS SANTOS. "CONTROL STRATEGY OF A GAS TURBINE." PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO, 2012. http://www.maxwell.vrac.puc-rio.br/Busca_etds.php?strSecao=resultado&nrSeq=21016@1.

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PONTIFÍCIA UNIVERSIDADE CATÓLICA DO RIO DE JANEIRO
Após um período de baixa nas bacias hidrográficas, o Brasil investiu em novas fontes de geração de energia elétrica. O gás natural é um dos exemplos destas novas fontes de energia. Dentre as usinas usuárias deste combustível, existem aquelas que operam com turbinas a gás. Muitos estudos sobre modelagem de turbinas a gás, simulação de desempenho, diagnóstico e controle começaram devido a importância dessas usinas. Assim, torna-se necessário que estas usinas trabalhem com segurança e confiabilidade. Para garantir esta estabilidade, é necessário o desenvolvimento de um sistema de controle, capaz de realizar esta operação de geração de energia elétrica de forma satisfatória. O sistema de controle utilizado por estes equipamentos é o objeto de estudo deste trabalho. Neste trabalho, foi utilizado um modelo computacional de uma turbina a gás com duas características principais: um modelo computacional do sistema de controle, desenvolvido com base em uma nova metodologia de controle de turbina a gás, e um modelo termodinâmico existente de uma turbina a gás ligado à rede brasileira. O sistema de controle utiliza a temperatura de saída da turbina a gás (TET), como um fator de correção, para ajustar a temperatura da entrada da turbina (TIT). Esta temperatura (TIT) é utilizada como referência para o controle de fluxo de combustível injetado no interior da câmara de combustão. O modelo também controla o VIGV (pás diretoras móveis na entrada do compressor) através de uma curva utilizada no controle desta turbina a gás ligada à rede brasileira. O modelo computacional ainda apresenta um cálculo simplificado da composição molar dos gases de exaustão desta máquina térmica. Esta característica pode ser usada em combinação com um modelo de uma caldeira de recuperação de calor (HRSG), para simular uma condição de queima suplementar (duct burner), onde o principal objetivo é aumentar a potência produzida no ciclo. Os resultados da simulação foram comparados com os dados operacionais da usina brasileira.
After a period of water shortage, Brazil invested in new sources of electricity generation. Natural gas is an example of these new energy sources. Among these plants, some operate with gas turbines. Many studies about gas turbine modeling, performance´s simulation, diagnosis and control have started due the importance of these power plants. Thus, it is necessary that these plants work safely and reliably. To ensure this stability, it is necessary to develop a control system capable of performing this operation for generating electricity in a satisfactory manner. Then, the control system used by this equipment becomes the objective of this study. In this work, a computational model of a gas turbine was used with two main features: a developed computational model of control system based on a new methodology of gas turbine control and an existing thermodynamic model of a gas turbine connected to the Brazilian grid. The control system uses the turbine exhaust temperature (TET) as a corrective factor to adjust the turbine inlet temperature (TIT). TIT was used as a setpoint to control the fuel flow injected inside the combustor. The model also controls the IGV (Inlet Guide Vanes) by a control curve used in control of a specific gas turbine. There is a simplified calculation of the molar composition of the exhaust gas. This feature could be used in combination with a model of a heat recovery steam generator (HRSG) to simulate a condition with duct burners where the main objective is increase the cycle power. The results of simulation were compared to the operational data from the Brazilian power plant.
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Wyse, Saffron Gale. "Automated optimisation of gas turbine combustors." Thesis, University of Cambridge, 2008. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.612335.

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25

Olivi, Alessandro. "Survival analysis of gas turbine components." Thesis, Linköpings universitet, Statistik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-129707.

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Survival analysis is applied on mechanical components installed in gas turbines. We use field experience data collected from repair inspection reports. These data are highly censored since the exact time-to-event is unknown. We only know that it lies before or after the repair inspection time. As event we consider irreparability level of the mechanical components. The aim is to estimate survival functions that depend on the different environmental attributes of the sites where the gas turbines operate. Then, the goal is to use this information to obtain optimal time points for preventive maintenance. Optimal times are calculated with respect to the minimization of a cost function which considers expected costs of preventive and corrective maintenance. Another aim is the investigation of the effect of five different failure modes on the component lifetime. The methods used are based on the Weibull distribution, in particular we apply the Bayesian Weibull AFT model and the Bayesian Generalized Weibull model. The latter is preferable for its greater flexibility and better performance. Results reveal that components from gas turbines located in a heavy industrial environment at a higher distance from sea tend to have shorter lifetime. Then, failure mode A seems to be the most harmful for the component lifetime. The model used is capable of predicting customer-specific optimal replacement times based on the effect of environmental attributes. Predictions can be also extended for new components installed at new customer sites.
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Allcock, D. C. J. "Abradable stator gas turbine labyrinth seals." Thesis, Cranfield University, 1999. http://dspace.lib.cranfield.ac.uk/handle/1826/10702.

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This is a detailed study into the internal aerodynamics of labyrinth seals, with pmic| reference to the effects of abradable honeycomb stators on labyrinth seal leakage.- A extensive experimental programme established tables of friction factor for three different grades of honeycomb used by industry, and examined the effect of both Reynolds number and clearance on these friction factors. The friction factor associated with a aerodynamically smooth surface was also experimentally determined in order to establish the experimental method. The experimental data was used to model the different grades of honeycomb used as stator material in numerical simulations of a number labyrinth seals, and allowed for comparison of the leakage associated with both smooth and abradable stator straight through labyrinth seals. Step-up and step-down seal geometries were also considered, and the effects of pressure ratio, clearance and rotation on labyrinth seal leakage was examined on all modelled seal types. This numerically generated leakage data was comprehensive enough to allow for the creation of a second-generation one-dimensional labyrinth seal leakage predictor tool of the type used by design engineers in network models. This tool accounts for stator material, seal clearance, overall pressure ratio, rotation and seal geometry, and the accuracy associated with this tool allows labyrinth seal leakage to b predicted to within 10%. Functions of discharge coefficient and carry-over factor obtained from the numerical predictions are used by this tool, and as such it is capable of dealing with a large number of different operating conditions for all the seal types modelled.
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Jasuja, A. K. "Structure of gas turbine fuel sprays." Thesis, Cranfield University, 2001. http://dspace.lib.cranfield.ac.uk/handle/1826/10729.

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28

Son, Changmin. "Gas turbine impingement cooling system studies." Thesis, University of Oxford, 2005. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.670200.

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29

Apostolidis, Asteris. "Turbine cooling and heat transfer modelling for gas turbine performance simulation." Thesis, Cranfield University, 2015. http://dspace.lib.cranfield.ac.uk/handle/1826/9234.

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The successful design of cooling systems for gas turbine engines is a key factor to feasibility of new projects, as the trend for increasing turbine entry temperatures implies requirements for more sophisticated cooling methods. This work focuses on the prediction of cooling performance of turbines, starting from local heat transfer effects at the surface of blades and vanes and expanding to performance simulation of cooled high pressure turbines and engines. In this context, this thesis establishes a new method that investigates the following topics: • The connection between the gas flow field around a cooled blade or vane and the prediction of cooling requirements of the setup. • The connection between a detailed gas flow field around a cooled blade or vane and a preliminary estimation of its metal temperature. • The effect that blade cooling requirements prediction has towards the performance simulation of a cooled turbine and the difference in results between turbine models of different axial resolution. • A simulation platform that includes the aforementioned topics under a web-based gas turbine performance simulation program. The first two objectives are tackled by developing a preliminary cooling design framework, which performs the needed convective and conductive heat transfer calculations between the gas and the blade, the blade and the coolant, and within the blade material. The method divides the geometry into a finite number of volumes, where heat transfer calculations are performed for steady-state conditions. One- and two-dimensional results show a good agreement with previous experimental work. The results suggest that chord resolution for blade heat transfer prediction is essential for a more accurate coolant temperature and mass flow rate prediction. In addition, conduction modelling has a dominant effect in heat transfer prediction of blades with steep temperature gradients. The third objective is achieved by associating the coolant state before mixing with the main stream and the results in turbine performance. The coolant temperature and mass flow rate prediction have a significant impact on turbine work and thermodynamic efficiency, figures highlighted as well for different turbine axial resolution methods. The results suggest that as the coolant heats up through a blade or vane and eventually mixes with the main flow, it contributes significantly towards the predicted turbine work, affecting as well the overall engine performance results, such as specific fuel consumption and specific thrust. A multistage turbine model is most suitable for capturing these effects, but it requires a number of additional inputs. Finally, the thesis suggests that a simulation framework such as the aforementioned, it can be of high usability and applicability if implemented on the cloud, rather than locally installed.
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Martinez-Tamayo, Federico. "The impact of evaporatively cooled turbine blades on gas turbine performance." Thesis, Massachusetts Institute of Technology, 1995. http://hdl.handle.net/1721.1/47385.

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31

Eriksson, Sara. "Development of catalysts for natural gas-fired gas turbine combustors." Doctoral thesis, Stockholm : Department of Chemical and Engineering and Technology, School of Chemical Science and Engineering, KTH - Royal Institute of Technology, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-4239.

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32

Smith, Warren Robert. "High velocity gas journal bearings." Thesis, University of Oxford, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.317910.

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33

Smith, Christopher Stephen. "Experimental Validation of a Hot Gas Turbine Particle Deposition Facility." The Ohio State University, 2010. http://rave.ohiolink.edu/etdc/view?acc_num=osu1269547595.

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34

Main, A. D. J. "Annular turbine cascade aerodynamics." Thesis, University of Oxford, 1994. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.239350.

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35

Batt, J. J. M. "Three-dimensional unsteady gas turbine flow measurement." Thesis, University of Oxford, 1997. http://ora.ox.ac.uk/objects/uuid:3302ca8f-0618-4440-9e23-3bf99bc3705d.

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The high pressure turbine stage can be considered the most important component for the efficiency and longevity of a modern gas turbine. The flow field within this stage is highly complex and is both unsteady and three-dimensional. Understanding this flow field is essential if improvements are to be made to future engine designs. Increasingly designers are placing more emphasis on the use of Computational Fluid Dynamics (CFD) rather than experimental results. CFD methods can be more flexible and cost effective. However before these predictions can be used they must be validated against experimental data at engine conditions. The hostile environment and complexity of flows within a gas turbine engine mean that collection of experimental data is extremely challenging. This thesis describes the development of an instrumentation technique for unsteady gas turbine flow measurement capable of resolving unsteady three-dimensional flow. The technique is based on an aerodynamic probe constructed with miniature semiconductor pressure transducers manufactured by Kulite Semiconductor Inc. Measurements recorded using this instrumentation technique from the Oxford Rotor experiment are presented to illustrate its use, and these in turn are compared with a CFD prediction of the rotor flow-field. This work was funded by the Engineering and Physical Sciences Research Council and Kulite Semiconductor Inc. The Oxford Rotor project is jointly funded by the Engineering and Physical Sciences Research Council (EPSRC), and Rolls-Royce Plc.
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36

Spelling, James. "Hybrid Solar Gas-Turbine Power Plants : A Thermoeconomic Analysis." Doctoral thesis, KTH, Kraft- och värmeteknologi, 2013. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-121315.

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The provision of a sustainable energy supply is one of the most importantissues facing humanity at the current time, and solar thermal power hasestablished itself as one of the more viable sources of renewable energy. Thedispatchable nature of this technology makes it ideally suited to forming thebackbone of a future low-carbon electricity system.However, the cost of electricity from contemporary solar thermal power plantsremains high, despite several decades of development, and a step-change intechnology is needed to drive down costs. Solar gas-turbine power plants are apromising new alternative, allowing increased conversion efficiencies and asignificant reduction in water consumption. Hybrid operation is a furtherattractive feature of solar gas-turbine technology, facilitating control andensuring the power plant is available to meet demand whenever it occurs.Construction of the first generation of commercial hybrid solar gas-turbinepower plants is complicated by the lack of an established, standardised, powerplant configuration, which presents the designer with a large number ofchoices. To assist decision making, thermoeconomic studies have beenperformed on a variety of different power plant configurations, includingsimple- and combined-cycles as well as the addition of thermal energy storage.Multi-objective optimisation has been used to identify Pareto-optimal designsand highlight trade-offs between costs and emissions.Analysis of the simple-cycle hybrid solar gas-turbines revealed that, whileelectricity costs were kept low, the achievable reduction in carbon dioxideemissions is relatively small. Furthermore, an inherent trade-off between thedesign of high efficiency and high solar share hybrid power plants wasidentified. Even with the use of new optimised designs, the degree of solarintegration into the gas-turbine did not exceed 63% on an annual basis.In order to overcome the limitations of the simple-cycle power plants, twoimprovements were suggested: the integration of thermal energy storage, andthe use of combined-cycle configurations. Thermal energy storage allowed thedegree of solar operation to be extended, significantly decreasing carbondioxide emissions, and the addition of a bottoming-cycle reduced the electricitycosts. A combination of these two improvements provided the bestperformance, allowing a reduction in carbon dioxide emissions of up to 34%and a reduction in electricity costs of up to 22% compared to a combination ofconventional power generation technologies.
Hållbar energiförsörjning är för närvarande en av de viktigaste frågorna förmänskligheten. Koncentrerad solenergi är nu etablerad som en tillförlitlig källaav förnybar energi. Den reglerbara karaktären hos tekniken gör den specielltintressant för uppbyggnaden av ett framtida koldioxidsnålt elsystem.Kostnaden för elektricitet från nuvarande termiska solkraftverk är hög trottsflera decennier av utveckling. Ett genombrått på tekniknivå krävs för att drivaned kostnaderna. Sol-gasturbiner är ett av de mest lovande alternativen, somger en ökad verkningsgrad samtidigt som vattenkonsumtionen reducerasdrastiskt. Sol-gasturbintekniken gör det möjligt att blandköra solenergi ochandra bränslen för att möta efterfrågan vid alla tidpunkter, en attraktiv aspekt iförhållande till alternativa lösningar.Uppbyggnaden av första generationens kommersiella hybrida solgasturbinkraftverkförsvåras dock av bristen på etablerade och standardiseradekraftverkskonfigurationer. Dessa ger planeraren ett stort antal valmöjlighetersom underlag för beslutsfattande. Termoekonomiska studier har genomförtsför ett flertal olika kraftverkskonfigurationer, däribland kraftverk med enkelcykel, kombikraftverk samt möjligheten att utnyttja termisk energilagring.Pareto-optimala konfigurationer har identifierats med hjälp av multiobjektsoptimeringför att belysa balansen mellan kostnader och utsläpp.Analysen av det enkla hybrida sol-gasturbinkraftverket visade attelektricitetskostnaden hållits på en låg nivå, men att den möjliga minskningen avkoldioxidutsläpp är relativt liten. Dessutom identifierades en inre balans mellanatt bibehålla en hög verkningsgrad hos konfigurationen och en hög andelsolenergi i produktionen. Andelen av solenergi i gasturbinen överskred aldrig63% på årlig bas, även med optimerade kraftverkskonfigurationer.Två förbättringar föreslås för att övervinna begränsningarna hos kraftverk medenkel cykel: integration av termisk energilagring samt nyttjande avkombikraftverkskonfigurationer. Termisk energilagring tillåter en ökad andelsolenergi i driften och reducerar koldioxidutsläppen drastiskt, medan denytterligare cykeln hos kombikraftverket reducerar elektricitetskostnaden.Kombinationen av dessa förbättringar ger den bästa prestandan, med enreduktion av koldioxidutsläppen på upp till 34% och reducerade elektricitetskostnaderpå upp till 22% i jämförelse med andra kombinationer avkonventionella kraftverkskonfigurationer.

QC 20130503

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37

Psarra, Aikaterini. "Gas turbine shaft failure modelling friction and wear modelling of turbines in contact." Thesis, Cranfield University, 2010. http://dspace.lib.cranfield.ac.uk/handle/1826/8348.

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A possible shaft failure event can trigger a number of mechanisms affecting the mechanical integrity particular of turbine discs and blades. A predominant aim in engine design and development is to satisfy that passenger lives are not to be endangered by the release of high energy debris. In a typical Intermediate Pressure shaft failure scenario of a 3-spool high bypass ratio turbofan engine, a potential mechanism to limit the terminal speed of the free running turbine, within acceptable values, is proven to be the impact of the free running turbine with the following stationary arrangement. Cont/d.
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38

Stitzel, Sarah M. "Flow Field Computations of Combustor-Turbine Interactions in a Gas Turbine Engine." Thesis, Virginia Tech, 2001. http://hdl.handle.net/10919/30992.

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The current demands for higher performance in gas turbine engines can be reached by raising combustion temperatures to increase thermal efficiency. Hot combustion temperatures create a harsh environment which leads to the consideration of the durability of the combustor and turbine sections. Improvements in durability can be achieved through understanding the interactions between the combustor and turbine. The flow field at a combustor exit shows non-uniformities in pressure, temperature, and velocity in the pitch and radial directions. This inlet profile to the turbine can have a considerable effect on the development of the secondary flows through the vane passage. This thesis presents a computational study of the flow field generated in a non-reacting gas turbine combustor and how that flow field convects through the downstream stator vane. Specifically, the effect that the combustor flow field had on the secondary flow pattern in the turbine was studied. Data from a modern gas turbine engine manufacturer was used to design a realistic, low speed, large scale combustor test section. This thesis presents the results of computational simulations done in parallel with experimental simulations of the combustor flow field. In comparisons of computational predictions with experimental data, reasonable agreement of the mean flow and general trends were found for the case without dilution jets. The computational predictions of the combustor flow with dilution jets indicated that the turbulence models under-predicted jet mixing. The combustor exit profiles showed non-uniformities both radially and circumferentially, which were strongly dependent on dilution and cooling slot injection. The development of the secondary flow field in the turbine was highly dependent on the incoming total pressure profile. For a case with a uniform inlet pressure in the near-wall region no leading edge vortex was formed. The endwall heat transfer was found to also depend strongly on the secondary flow field, and therefore on the incoming pressure profile from the combustor.
Master of Science
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39

Zedda, M. "Gas turbine engine and sensor fault diagnosis." Thesis, Cranfield University, 1999. http://dspace.lib.cranfield.ac.uk/handle/1826/9117.

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Substantial economic and even safety related gains can be achieved if effective gas turbine performance analysis is attained. During the development phase, analysis can help understand the effect on the various components and on the overall engine performance of the modifications applied. During usage, analysis plays a major role in the assessment of the health status of the engine. Both condition monitoring of operating engines and pass off tests heavily rely on the analysis. In spite of its relevance, accurate performance analysis is still difficult to achieve. A major cause of this is measurement uncertainty: gas turbine measurements are affected by noise and biases. The simultaneous presence of engine and sensor faults makes it hard to establish the actual condition of the engine components. To date, most estimation techniques used to cope with measurement uncertainty are based on Kalman filtering. This classic estimation technique, though, is definitely not effective enough. Typical Kalman filter results can be strongly misleading so that even the application of performance analysis may become questionable. The main engine manufactures, in conjunction with research teams, have devised modified Kalman filter based techniques to overcome the most common drawbacks. Nonetheless, the proposed methods are not able to produce accurate and reliable performance analysis. In the present work a different approach has been pursued and a novel method developed, which is able to quantify the performance parameter variations expressing the component faults in presence of noise and a significant number of sensor faults. The statistical basis of the method is sound: the only accepted statistical assumption regards the well known measurement noise standard deviations. The technique is based on an optimisation procedure carried out by means of a problem specific, real coded Genetic Algorithm. The optimisation based method enables to concentrate the steady state analysis on the faulty engine component(s). A clear indication is given as to which component(s) is(are) responsible for the loss of performance. The optimisation automatically carries out multiple sensor failure detection, isolation and accommodation. The noise and biases affecting the parameters setting the operating point of the engine are coped with as well. The technique has been explicitly developed for development engine test bed analysis, where the instrumentation set is usually rather comprehensive. In other diagnostic cases (pass off tests, ground based analysis of on wing engines), though, just few sensors may be present. For these situations, the standard method has been modified to perform multiple operating point analysis, whereby the amount of information is maximised by simultaneous analysis of more than a single test point. Even in this case, the results are very accurate. In the quest for techniques able to cope with measurement uncertainty, Neural Networks have been considered as well. A novel Auto-Associative Neural Network has been devised, which is able to carry out accurate sensor failure detection and isolation. Advantages and disadvantages of Neural Network-based gas turbine diagnostics have been analysed.
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40

Jonas, Susanne. "Automatic Status Logger For a Gas Turbine." Thesis, Linköping University, Department of Science and Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11020.

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The Company Siemens Industrial Turbo Machinery AB manufactures and launches in operation among other things gas turbines, steam turbines, compressors, turn-key power plants and carries out service for components for heat and power production. Siemens also performs research and development, marketing, sales and installations of turbines and completes power plants, service and refurbish.

Our thesis for the engineering degree is to develop an automatic status log which will be used as a tool to control how the status of the machine is before and after technical service at gas turbines. Operational disturbances will be registered in a structured way in order to get a good possibility to follow up the reliability of the application.

An automatic log function has been developed and will be activated at start, stop and shutdown of the turbine system. Log files are created automatically and get a name with the event type, the date and the time. The files contain data as timestamp, name, measured values and units of the signals which are going to be analyzed by the support engineers. They can evaluate the cause of the problem using the log files.

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41

García, Edith. "Automatic Status Logger for a Gas Turbine." Thesis, Linköping University, Department of Science and Technology, 2007. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-11590.

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The Company Siemens Industrial Turbo Machinery AB manufactures and launches in operation among other things gas turbines, steam turbines, compressors, turn-key power plants and carries out service for components for heat and power production. Siemens also performs research and development, marketing, sales and installations of turbines and completes power plants, service and refurbish.

Our thesis for the engineering degree is to develop an automatic status log which will be used as a tool to control how the status of the machine is before and after technical service at gas turbines. Operational disturbances will be registered in a structured way in order to get a good possibility to follow up the reliability of the application.

An automatic log function has been developed and will be activated at start, stop and shutdown of the turbine system. Log files are created automatically and get a name with the event type, the date and the time. The files contain data as timestamp, name, measured values and units of the signals which are going to be analyzed by the support engineers. They can evaluate the cause of the problem using the log files.

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42

Klang, Henrik, and Andreas Lindholm. "Modelling and simulation of a gas turbine." Thesis, Linköping University, Department of Science and Technology, 2005. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-2893.

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In this thesis, a gas turbine simulator for the Siemens GT10C was developed and implemented.

It concerns everything from the theory behind the simulator; both the hard- ware and software involved, to how the actual simulator was built using these tools. The theory concerns itself with basic automatic control concepts, as well as basic turbine theory.

The simulator setup is being discussed concerning both technical and eco- nomic issues. A robust hardware solution is then selected, using the basic re- quirements, which the simulator then is built around.

The tools used are the Siemens SIMATIC automatic control system and the Siemens SIMIT real-time simulator using a SIMBA Pro PCI card to interface with the PLC:s in the SIMATIC system. Matlab are also used to a lesser extent to build the simulator behavior in SIMIT.

In the end, a fully featured simulator is presented that can be used for various purposes such as training operators, trying out new concepts and testing the automatic control system used to control the turbine.

Further development that could be done, by other engineers, in the future, is also discussed.

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43

Sundberg, Jenny. "Heat Transfer Correlations for Gas Turbine Cooling." Thesis, Linköping University, Department of Mechanical Engineering, 2006. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-5446.

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A first part of a ”Heat Transfer Handbook” about correlations for internal cooling of gas turbine vanes and blades has been created. The work is based on the cooling of vanes and blades 1 and 2 on different Siemens Gas Turbines. The cooling methods increase the heat transfer in the cooling channels by increasing the heat transfer coefficient and/or increasing the heat transfer surface area. The penalty paid for the increased heat transfer is higher pressure losses.

Three cooling methods, called rib turbulated cooling, matrix cooling and impingement cooling were investigated. Rib turbulated cooling and impingement cooling are typically used in the leading edge or mid region of the airfoil and matrix cooling is mostly applied in the trailing edge region.

Literature studies for each cooling method, covering both open literature and internal reports, were carried out in order to find correlations developed from tests. The correlations were compared and analyzed with focus on suitability for use in turbine conditions. The analysis resulted in recommendations about what correlations to use for each cooling method.

For rib turbulated cooling in square or rectangular ducts, four correlations developed by Han and his co-workers [3.5], [3.8], [3.9] and [3.6] are recommended, each valid for different channel and rib geometries. For U-shaped channels, correlations of Nagoga [3.4] are recommended.

Matrix cooling is relatively unknown in west, but has been used for many years in the former Soviet Union. Therefore available information in open literature is limited. Only one source of correlations was found. The correlations were developed by Nagoga [4.2] and are valid for closed matrixes. Siemens Gas Turbines are cooled with open matrixes, why further work with developing correlations is needed.

For impingement cooling on a flat target plate, a correlation of Florschuetz et al. [5.7] is recommended for inline impingement arrays. For staggered arrays, both the correlations of Florschuetz et al. [5.7] and Höglund [5.8] are suitable. The correlations for impingement on curved target plate gave very different results. The correlation of Nagoga is recommended, but it is also advised to consult the other correlations when calculating heat transfer for a specific case.

Another part of the work has been to investigate the codes of two heat transfer programs named Q3D and Multipass, used in the Siemens offices in Finspång and Lincoln, respectively. Certain changes in the code are recommended.

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44

Berg, Anton. "Flexible Ignition System for a Gas Turbine." Thesis, KTH, Kraft- och värmeteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-98378.

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Siemens Industrial Turbomachinery AB produce five gas turbines models. The SGT-700 can currently only start on gases which contain low amounts of inert gases. It is therefore of interest to widen the fuel range which the SGT-700, as well as other gas turbines, can start on. This report investigates the maximum limit of inert gases the SGT-700 will be able to start on, but also investigates if it is possible to start on liquid fuel (diesel) by making a few modifications to the gas turbine. To investigate this, the atmospheric combustion rig available at Siemens in Finspång has been used with a standard burner, igniter and ignition unit for the SGT-700. For the liquid fuel, the igniter was replaced by a torch igniter specially made for liquid fuels. Four different gases were evaluated; methane, propane, CO2 and N2 in order to see the effect of both various hydrocarbons and various inert gases. A model was developed for the gaseous experiments to estimate the limit for the maximum amount of inert gases the gas turbine would be able to start on. The model suggested that CO2 would require a larger amount of energy than N2 for the same amount in the composition, but that varying hydrocarbons did not have any effect if looking at the mass % of inert gas in the composition. The model was also extended with ethane and hydrogen but no experiments were performed with these gases. The model gave satisfying results. It overestimated the maximum amount of inert gases which could be mixed with propane, but agreed well when comparing the two inert gases with each other. Other interesting results were that an increased fuel flow decreased the minimum ignition energy and that an increased air flow gave a minor decrease in the maximum amount of inert gases that was possible to ignite. The torch igniter for the liquid fuel worked in a satisfying way. The ignition energy was however too low, so the ignition reliability was low. A new ignition unit with larger energy output therefore needs to be implemented. The igniter was fairly insensitive to variations in burner air flow and the ignition delay was small enough to provide a sustainable flame.
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45

Endale, Turie Samson. "Gas Turbine Plant Modeling for Dynamic Simulation." Thesis, KTH, Kraft- och värmeteknologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-93897.

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Gas turbines have become effective in industrial applications for electric and thermal energy production partly due to their quick response to load variations. A gas turbine power plant is a complex assembly of a varietyof components that are designed on the basis of aero thermodynamiclaws. This thesis work presents model development of a single-shaft gas turbine plant cycle that can operate at wide range of load settings in complete dynamic GTP simulator. The modeling and simulation has been done in Dymola 7.3, based on the Modelica programming language. The gas turbine plant model is developed on component-oriented basis. This means that the model is built up by smaller model classes. With this modeling approach, the models become flexible and user-friendly for different plant operational modes. The component models of the main steady-state compressor and turbine stages have been integrated with gas plenum models for capturing the performance dynamics of the gas turbine power plant. The method of assembly used for gas turbine plant integration is based on models of the components from an engineering process scheme. In order to obtain an accurate description of the gas-turbine working principle, each component is described by a non-linear set of both algebraic and first-order differential equations. The thesis project provides descriptions of the mathematical equations used for component modeling and simulation. A complete dynamic simulation of a gas-turbine plant has been performed by connecting the complete plant model with PI controllers for both design and off-design operating modes. Furthermore, turbine blade cooling has been studied to evaluate the changes in power output. This has been done to compare and analyze the blade cooling effect.
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46

Poppe, Christian. "Scalar measurements in a gas turbine combustor." Thesis, Imperial College London, 1997. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.264987.

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47

Kister, Guillaume. "Ceramic-matrix composites for gas turbine applications." Thesis, University of Bath, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.299850.

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48

Chleboun, Peter Victor. "Mathematical modelling relevant to gas turbine combustion." Thesis, University of Leeds, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.343286.

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49

Templalexis, I. K. "Gas turbine performance with distorted inlet flow." Thesis, Cranfield University, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.427101.

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50

Uyanwaththa, Asela R. "CFD modelling of gas turbine combustion processes." Thesis, Loughborough University, 2018. https://dspace.lboro.ac.uk/2134/34686.

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Stationary gas turbines manufacturers and operators are under constant scrutiny to both reduce environmentally harmful emissions and obtain efficient combustion. Numerical simulations have become an integral part of the development and optimisation of gas turbine combustors. In this thesis work, the gas turbine combustion process is analysed in two parts, a study on air-fuel mixing and turbulent combustion. For computational fluid dynamic analysis work the open-source CFD code OpenFOAM and STAR-CCM+ are used. A fuel jet injected to cross-flowing air flow is simplified air-fuel mixing arrangement, and this problem is analysed numerically in the first part of the thesis using both Reynolds Averaged Navier Stokes (RANS) method and Large Eddy Simulation (LES) methods. Several turbulence models are compared against experimental data in this work, and the complex turbulent vortex structures their effect on mixing field prediction is observed. Furthermore, the numerical methods are extended to study twin jets in cross-flow interaction which is relevant in predicting air-fuel mixing with arrays of fuel injection nozzles. LES methods showed good results by resolving the complex turbulent structures, and the interaction of two jets is also visualised. In this work, all three turbulent combustion regimes non-premixed, premixed, partially premixed are modelled using different combustion models. Hydrogen blended fuels have drawn particular interest recently due to enhanced flame stabilisation, reduced CO2 emissions, and is an alternative method to store energy from renewable energy sources. Therefore, the well known Sydney swirl flame which uses CH4: H2 blended fuel mixture is modelled using the steady laminar flamelet model. This flame has been found challenging to model numerically by previous researchers, and in this work, this problem has been addressed with improved combustion modelling approach with tabulated chemistry. Recognizing that the current and future gas turbine combustors operate on a mixed combustion regime during its full operational cycle, combustion simulations of premixed/partially premixed flames are also performed in this thesis work. Dynamical artificially thickened flame model is implemented in OpenFOAM and validated using propagating and stationary premixed flames. Flamelet Generated Manifold (FGM) methods are used in the modelling of turbulent stratified flames which is a relatively new field of under investigation, and both experimental and numerical analysis is required to understand the physics. The recent experiments of the Cambridge stratified burner are studied using the FGM method in this thesis work, and good agreement is obtained for mixing field and temperature field predictions.
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