Dissertations / Theses: 'Revision of steam turbine'

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Trněný, Bohumil. "Oprava a rekonstrukce parní turbiny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230035.

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The content of this diploma thesis is proposal of repair, reconstruction of equipment and installation of electrohydraulic regulation of steam turbine. Thesis is given for specific case. At the beginning there is a basic description of repairing turbine. The next part of thesis deals with checking of main turbine parts and recalculation of gland steam. In the following part there is revisional report with repair or exchange suggestions of demaged turbine parts, followed by description of turbine regulation reconstruction. The last part deals with economical evaluation used innovation and recommendations for repairment procedure.

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2

Jelínek, Tomáš. "Oprava turbínové skříně." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-320107.

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This diploma thesis deals with the repair of a steam backpressure single-stage turbine. This thesis is assigned to a specific Spilling turbine case. A revisional report of this turbine with repair or exchange suggestions of demaged turbine parts is processed. In addition, a simulation of the contact pressure is carried out on the split plane of the housing. Structural modifications are designed and simulated to increase the parting plane's tightness. Further, the calculation of the tightening torque of the split plane is performed and a control thermodynamic and strength calculation of the labyrinth seals is performed.

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3

Hlavinka, Miloslav. "Rekonstrukce protitlakové parní turbiny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2015. http://www.nusl.cz/ntk/nusl-231818.

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Tématem diplomové práce je revize parní turbíny Mitsubishi a výpočet utahovacích momentů šroubů dělící roviny. Tato práce je rozdělena do několika částí. Úvodní část práce obsahuje seznámení s rozsahem prováděných servisních prací na parních turbínách. Poté je zde samotná revize parní turbíny Mitsubishi. Tato revize je dělena podle jednotlivých komponent turbíny. Poté je zde stanoven seznam nutných oprav a také seznam doporučených oprav pro příští odstávku. V další části je zde shrnut výpočet utěsnění dělicích rovin a to s nebo bez odlehčení. Dále jsou rozebrány nejčastěji používané typy závitů spojovacího materiálu parních turbín. Hlavní částí práce je samotný výpočet utahovacího momentu. Výstupem této práce je poté program pro výpočet utahovacího momentu v programu Excel.

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4

Holečková, Michaela. "Rekonstrukce parní kondenzační turbíny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2016. http://www.nusl.cz/ntk/nusl-254346.

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The aim of this master thesis is the retrofit of a condensing steam turbine. The thesis obtains a revision of the steam turbine, the reconstruction of steam turbine blades and the basic calculation of bolt torques of the turbine split plane. The master thesis is assigned to a specific retrofit of the steam turbine Lang. In the introductory part the thesis is focused on the turbine description and the basic functions of selected turbine components. The following part deals with the revision and the proposal of repairs for all components and the recommendation of additional modernizations of specific measuring equipments. The analysis of anchoring the stator and rotor blading and their reconstruction is discussed in the next part. In the last part the thesis focuses on the sealing of the turbine split plane and the calculation of the various bolt torques closely linked to the sealing.

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5

Grepl, Martin. "Revize parní turbíny a návrh oprav." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2017. http://www.nusl.cz/ntk/nusl-316911.

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The theme of this master thesis is the revision and repair design of the condensing steam turbine SST 600 in Bielsko-Biala. The thesis deals with the revision of the steam turbine and the repair design of the damaged parts, the overall analysis of the separation of the steam of the split plane and the calculation of the parameters for tightening the new screws. The master thesis is given for a specific case. The introductory part of the master thesis deals with a basic description of the repaired steam turbine. Subsequently, a review of individual disassembled parts is given and the scope of the repairs is stated. In the next part of this thesis are summarized the causes of the steam leakage of the dividing plane at the points of the cross section and in the area of the control stage. The last part deals with the sealing problem of the split plane and the related main part of the master thesis is the calculation of the tightening parameters of bolts in the turbine housing. Another aim of the master thesis is to create drawings of the lightening of the split plane on turbine house.

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6

White, Alexander John. "Condensation in steam turbine cascades." Thesis, University of Cambridge, 1992. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.259523.

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7

Mitchell, K. C. "Weld repair of steam turbine rotors." Thesis, Swansea University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.638208.

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Turbine rotors are among the most critical and highly stressed components in steam power plants. Although relatively few instances of catastrophic rotor bursts have occurred, they have resulted in lengthy forced outages and severe economic penalties to the affected utilities. To forestall the possibility of a catastrophic burst, utilities will retire the rotors affected, generally to the original equipment manufacturer's (OEM's) recommendations. The criteria and methodology for determining which rotors should be retired are proprietary and vary among manufacturers. If utilities could extend the life of these rotors by 10-20 years, then substantial savings would be made. The principal method for extending their life is weld repair and over the last 20 years, there has been a substantial increase in the number of repairs combined with the complexity of repair adopted. This project was designed to evaluate the relationship between microstructure and properties of welds on ex-service steam turbine rotor steels, after applying appropriate welding parameters and weld bead deposition sequence to minimise heat input and produce acceptable microstructures. From the project work, it is clear that the LP, IP and HP ex-service rotor forgings selected were representative of UK manufactured rotor forgings. Although never intended for weld repair, NP have demonstrated their ability to repair these steels successfully and produce weldments with acceptable microstructures and mechanical properties.

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Wakeley, Guy Richard. "The optimisation of steam turbine design." Thesis, University of Newcastle Upon Tyne, 1997. http://hdl.handle.net/10443/2041.

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The world market-place for steam turbine products is becoming increasingly competitive, and manufacturers must routinely produce designs which are extensively optimised whilst working within demanding tender and contract lead-times. The objective of the research work has been to develop a methodology whereby established turbomachinery analysis methods can be integrated within a framework of optimising algorithms. A rule-base, numerical optimisation, fuzzy logic, and genetic algorithms are used to optimise bladepath configurations, with particular emphasis on the minimisation of life-cycle operating costs. Significantly, automation of the design process is increased, design lead-times can be reduced, and performance improvements are predicted. The optimisation procedure relies on a sequential approach, with much emphasis placed on the iterative running of simple design codes. Simplified design methods are often reliant on correlated loss data to predict turbine performance, and in some cases this data is inaccurate or incomplete. An example of this is in the design of partially-admitted control stages, where little published data is available. It is suggested that CFD methods can, in some cases, be applied to derive new performance correlations or re-assess the validity of existing models. The application of an unsteady CFD solver to typical control stage geometries is presented in detail, and the approach is extended to include the development of a new control stage optimisation method.

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9

Ding, Bowen. "Aerodynamics of low pressure steam turbine exhaust systems." Thesis, University of Cambridge, 2019. https://www.repository.cam.ac.uk/handle/1810/290137.

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The low pressure (LP) exhaust system presents a promising avenue for improving the performance of large steam turbines. For this reason, LP exhaust systems have attracted the attention of the research community for decades. Nevertheless, we still lack understanding of the flow physics and loss mechanisms in the exhaust system, especially at part-load conditions. It is also unclear how the exhaust system should be designed when its required operating range widens. This thesis provides solutions to these aerodynamic issues through experimental and numerical investigations, and provides tools that could contribute to better designs of LP exhaust systems. Firstly, the Computational Fluid Dynamics (CFD) solver ANSYS CFX was validated against experiments performed on a scaled test rig under representative part-load flow conditions. This validation exposed the weakness of Reynolds-averaged Navier-Stokes (RANS) CFD when there is a highly swirling flow and large separation regions in the exhaust diffuser. To facilitate the numerical studies, a series of tools were also developed. A design suite, ExhaustGen, was used to automate the pre- and post-processing of CFD calculations. The exhaust diffuser was parametrised using "Minimum Energy Curves", which reduce the dimension of parameter space. Further, a suitable stage-hood interface treatment (Multiple Mixing Planes) was chosen to predict the circumferentially non-uniform flow in the exhaust hood at low computational cost. Numerical investigation of the baseline geometry provided insights into the key flow features and loss mechanisms in the exhaust system, over a wide range of operating conditions. In particular, the bearing cone separation was identified as a key source of loss at part-load conditions. The effect of stage-hood interaction on the performance and design of the exhaust system was studied by varying the rotor blade design, which can positively influence system performance. Finally, a global sensitivity study was performed to identify the most influential design parameters of the exhaust hood. These findings allow, for the first time, LP exhaust hood performance maps to be constructed, so that the benefits of choosing a suitable hood geometry and blade design can be revealed. The thesis also offers contribution towards formulating LP exhaust system design guidance for a wide operating range.

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Topel, Monika. "Steam Turbine Thermal Modeling for Improved Transient Operation." Licentiate thesis, KTH, Kraft- och värmeteknologi, 2014. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-156196.

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The growing shares of renewable energy sources in the market and solar thermal power applications have set higher requirements on steam turbine operation.These requirements are related to flexibility during transients. A key aspect sought of such flexibility is the capability for fast starts. Due to the varying temperature gradients during start-up, the speed at which the turbine can start is constrained by thermal stresses and differential expansion. These phenomena either consume component lifetime or may result in machine failure if not carefully controlled. In order to accomplish faster starts while ensuring that lifing requirements are preserved, it is important to analyze the thermal behavior of the machine. For this, a transient thermal model was developed with a focus on adaptability to different turbine sizes and geometries. The model allows for simple and fast prediction of thermo-mechanical properties within the turbine metal, more importantly, of the temperature distribution and the associated thermal expansion. The next step of this work was to validate the assumptions and simplifications of the model. This was done through the study and comparison of two turbines against measured operational data from their respective power plants. Furthermore,validation studies also included comparisons concerning the geometric detail level of the model. Overall, comparison results showed a large degree of agreement with respect to the measured data and between the geometric detail levels. The validated model was then implemented in studies related to reducing start-up times and peak differential expansion. For this, the potential effects of turbine temperature maintaining modifications were investigated and quantified.The modifications studied included: increasing gland steam pressure, increasing back pressure and increasing barring speed. Results yielded significant improvements starting from 9.5% in the start-up times and 7% in the differential expansion.

QC 20141128

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11

Neerputh, Rahendra Laljith. "Development of appropriate steam turbine models in Flownex." Master's thesis, University of Cape Town, 2014. http://hdl.handle.net/11427/13158.

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Includes bibliographical references.
The Specialization Centre for Energy Efficiency at the University of Cape Town has a goal of building thermo-hydraulic models of an entire power plant. A one-dimensional thermo-hydraulic network solver, Flownex, is the software envisaged to accomplish this goal. The development of appropriate steam turbine models in Flownex supports fulfilment of this goal. Steam turbines of fossil and nuclear power plants make up most of the generating capacity for the majority of industrialised and industrial developing countries, except for those whose power industry depends mainly on hydroelectric power plants [1]. It is therefore a matter of great interest to be ab le to predict the steady state and transient operation of steam turbines. The aim of this dissertation was to use minimal data that was readily available to the end user to develop accurate models. Acceptance test data was used as the primary source because it is more reliable than plant data. Various pressure drop correlations and methods to predict off-design efficiency were investigated. These correlations and methods were solved analytically and implemented in Flownex. Interpretation of the error analysis for the pressure drop correlations established that the general empirical law using inlet conditions and Stodola law in the volume form were the most accurate and consistent in predicting mass flow rate and pressure. The Ray method was shown to be the most accurate to predict off-design efficiency and one of the less complicated to implement. Steady state models were built for four turbine trains using the general empirical and Stodola laws. The results produced by both correlations were similar, showing that for high vacuum conditions either correlation could be used. The general empirical law was the chosen correlation to implement for transient analysis since it was generally more accurate and easier to implement than Stodola. The power predicted by the model was within ±1 % of that of the actual power produced.

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12

Spelling, James. "Steam Turbine Optimisation for Solar Thermal Power Plant Operation." Licentiate thesis, KTH, Kraft- och värmeteknologi, 2011. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-35386.

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The provision of a sustainable energy supply is one of the most important issues facing humanity at the current time, given the strong dependence of social and economic prosperity on the availability of affordable energy and the growing environmental concerns about its production. Solar thermal power has established itself as a viable source of renewable power, capable of generating electricity at some of the most economically attractive rates. Solar thermal power plants are based largely on conventional Rankine-cycle power generation equipment, reducing the technological risk involved in the initial investment. Nevertheless, due to the variable nature of the solar supply, this equipment is subjected to a greater range of operating conditions than would be the case in conventional systems. The necessity of maintaining the operational life of the steam-turbines places limits on the speed at which they can be started once the solar supply becomes available. However, in order to harvest as much as possible of the Sun’s energy, the turbines should be started as quickly as is possible. The limiting factor in start-up speed being the temperature of the metal within the turbines before start-up, methods have been studied to keep the turbines as warm as possible during idle-periods. A detailed model of the steam-turbines in a solar thermal power plant has been elaborated and validated against experimental data from an existing power plant. A dynamic system model of the remainder of the plant has also been developed in order to provide input to the steam-turbine model. Three modifications that could potentially maintain the internal temperature of the steam-turbines have been analysed: installation of additional insulation, increasing the temperature of the gland steam and use of external heating blankets. A combination of heat blankets and gland steam temperature increase was shown to be the most effective, with increases in electricity production of up to 3% predicted on an annual basis through increased availability of the solar power plant.
Hållbar energiförsörjning är för närvarande en av de viktigaste frågorna för mänskligheten. Socialt och ekonomiskt välstånd är starkt kopplat till rimliga energipriser och hållbar energiproduktion. Koncentrerad solenergi är nu etablerad som en tillförlitlig källa av förnybar energi och är också ett ekonomiskt attraktivt alternativ. Koncentrerade solenergikraftverk bygger till stor del på konventionella Rankine-cykel elgeneratorer, vilka minskar de tekniskt relaterade riskerna i den initiala investeringen. På grund av solstrålningens skiftande karaktär utsätts denna utrustning för mer varierade driftsförhållanden, jämfört med konventionella system. Behovet av att bibehålla den operativa livslängden på ångturbiner sätter gränser för uppstartshastigheten. För att utnyttja så mycket som möjligt av solens energi bör ångturbinen startas så snabbt som möjligt när solstrålningen blir tillgänglig. Eftersom temperaturen i metalldelar hos turbinerna är den begränsande faktorn, har metoder studerats för att hålla turbinerna så varma som möjligt under tomgångsperioder. En detaljerad modell av ångturbiner i ett solenergikraftverk har utvecklats och validerats mot experimentella data från ett befintligt kraftverk. En dynamisk systemmodell av de övriga delarna av anläggningen har också utvecklats för att ge input till ångturbinsmodellen. Tre modifieringar som potentiellt kan bidra till att upprätthålla den inre temperaturen i ångturbiner har analyserats: montering av ytterligare isolering, ökning av temperaturen hos glänsångan och användning av elvärmefiltar. En kombination av elvärmefiltar och en temperaturökning av glänsångan visade sig vara det mest effektiva alternativet. Åtgärderna resulterade i en ökad elproduktion på upp till 3%, beräknat på årsbasis genom ökad tillgänglighet hos kraftverket.
QC 20110629
TURBOKRAFT

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13

Waite, Jason S. "The application of brush seals to steam turbine generators." Thesis, Northumbria University, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.367419.

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McCallum, Marcus Anthony. "The simulation of wet steam flow in a turbine." Thesis, University of Strathclyde, 1998. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.366697.

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Nunes, Bonaventure R. "Numerical Loss Prediction of high Pressure Steam Turbine airfoils." Thesis, Virginia Tech, 2013. http://hdl.handle.net/10919/51742.

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Steam turbines are widely used in various industrial applications, primarily for power extraction. However, deviation for operating design conditions is a frequent occurrence for such machines, and therefore, understanding their performance at off design conditions is critical to ensure that the needs of the power demanding systems are met as well as ensuring safe operation of the steam turbines. In this thesis, the aerodynamic performance of three different turbine airfoil sections ( baseline, mid radius and tip profile) as a function of angle of incidence and exit Mach numbers, is numerically computed at 0.3 axial chords downstream of the trailing edge. It was found that the average loss coefficient was low, owing to the fact that the flow over the airfoils was well behaved. The loss coefficient also showed a slight decrease with exit Mach number for all three profiles. The mid radius and tip profiles showed near identical performance due to similarity in their geometries. It was also found out that the baseline profile showed a trend of substantial increase in losses at positive incidences, due to the development of an adverse pressure zone on the blade suction side surface. The mid radius profile showed high insensitivity to angle of incidence as well as low exit flow angle deviation in comparison to the baseline blade.
Master of Science

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McFarland, Jacob Andrew. "Conceptual Design and Instrumentation Study for a 2-D, Linear, Wet Steam Turbine Cascade Facility." Thesis, Virginia Tech, 2008. http://hdl.handle.net/10919/36165.

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The design of last stage low pressure steam (LP) turbines has become increasingly complicated as turbine manufacturers have pushed for larger and more efficient turbines. The tip sections of these LP turbines encounter condensing wet steam at high velocities resulting in increased losses. These losses are difficult to predict with computational fluid dynamic models. To study these losses and improve the design of LP turbines a study was commissioned to determine the feasibility and cost of a steam cascade facility for measuring low pressure turbine blade tip section aerodynamic and thermodynamic performance.

This study focused on two objectives: 1) design a steam production facility capable of simulating actual LP turbine operating conditions, and 2) design an instrumentation system to measure blade performance in wet steam. The steam production facility was designed to allow the test section size to be selected later. A computer code was developed to model the facility cycle and provide equipment requirements. Equipment to meet these requirements, vendors to provide it, and costs were found for a range of test section sizes. A method to control the test section conditions was also developed.

To design the instrumentation system two methods of measuring blade losses through entropy generation were proposed. The first method uses existing total pressure probe techniques. The second method uses advanced particle imaging velocimetry techniques possibly for the first time in wet steam. A new method is then proposed to modify the two techniques to take measurements at non-equilibrium states. Finally accuracy issues are discussed and the challenges associated with achieving periodic flow in this facility are investigated.
Master of Science

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Novak, Luke Michael. "Numerical Investigation of Vibration in a Steam Turbine Control Valve." Thesis, North Dakota State University, 2017. https://hdl.handle.net/10365/28042.

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A numerical analysis is performed at North Dakota State University to investigate and resolve steam inlet control valve vibration in a Minnkota Power Cooperative turbine. Pressure fluctuations resulting from an unstable flow pattern are found to cause vibration. Multiple valve disc and seat design modifications to stabilize the flow are made and tested. The full scale geometry is used with steam as the working material. Both steady-state and transient analyses are completed. Analytical calculations are used for verification. Investigation of all modifications is discussed. Results from the original valve configuration show vortex shedding off of the disc. A currently installed cutoff disc has not removed flow-induced vibration. Flow expansion generates unstable flow, creating an unsteady separation bubble on the valve seat at the throat exit. Changing the throat from a converging-diverging to a purely converging nozzle stabilizes the flow, removing the flow-induced pressure forces causing disc vibration.

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Qi, Di. "Establishment of an open 3D steam turbine flutter test case." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-200744.

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An open three-dimensional (3D) flutter test case for steam turbines is presented. Unlike previous research on turbine flutter, the geometry is an open resource and is from a test case originally presented by Durham University. The geometry of the test case includes the stator, rotor and diffuser, which is representative of the aerodynamic characteristics of modern steam turbine blading. The average inlet flow conditions are total pressure 27 kPa and total temperature 340 K which are typical for the last stage. The average static pressure at the exit of the diffuser is 8800 Pa. It also provides the typical flow conditions for the last stage steam turbine.The aim of current study is to define a 3D test case for open realistic steam turbine blades flutter analysis. Commercial numerical tool ANSYS CFX was used to solve Reynolds-averaged Navier-Stokes (RANS) equations for viscous flow and Laminar equations for inviscid flow for steady and unsteady state. The defined mode shape for the test case was the first flap bending mode fixed at the hub. Multi-row steady state simulations with mixing plane were performed for different length of rotor exit. Reflecting waves was found to influence both steady and unsteady simulation at the mixing plane and rotor outlet. Only the rotor was considered for the flutter analysis. The plots of normalised aerodynamic damping and local work coefficient for different Inter Blade Phase Angle (IBPA) were calculated. It showed that -90 degrees IBPA was least stable. Unsteady aerodynamic work was done mainly on the tip region of rotor blade. Initial results of tip clearance flow were only studied in the steady state.This thesis work is partly included in paper written for European Turbomachinery Conference (ETC). It is verified by comparing the results obtained from CFX and LUFT (Linearized Unsteady Flow solver for Turbomachinery) solvers.
Ett testfall för analys av svängningar i ångturbinsblad utifrån en öppen tredimensionell (3D) modell presenteras i denna rapport. Till skillnad från tidigare undersökningar av turbinbladssvängningar är geometrin i detta fall allmänt tillgänglig via ett testfall ursprungligen presenterat av Durham University. Denna geometri inkluderar stator, rotor och diffusor, vilket är representativt för de aerodynamiska egenskaperna hos moderna ångturbiners bladuppsättning. Inloppsförhållandena var ett totaltryck på i genomsnitt 27 kPa och en total temperatur på i genomsnitt 340 K, vilket är typiskt för det sista turbinsteget. Det genomsnittliga statiska trycket vid diffusorns utlopp var 8800 Pa, också det typiskt för förhållandena vid det sista steget i en ångturbin.Studiens syfte var att definiera ett 3D-testfall för realistisk analys av öppen turbinbladssvängning. Kommersiell mjukvara (ANSYS CFX) användes för att lösa RANS-ekvationer (Reynolds-averaged Navier Stokes) för visköst flöde och för ekvationer gällande laminärt flöde vid icke-visköst flöde, för stationära och icke-stationära fall. Testfallets definierade böjmod var första böjmod med turbinbladets ena ände fixerad. Stationära simuleringar av multipla turbinrader med mixing-plane-metoden genomfördes för olika längd på rotorutloppet. Vågreflektion upptäcktes påverka både stationär och icke-stationär simulering vid mixing plane-läget och rotorutloppet.För svängningsanalysen av turbinbladen undersöktes endast rotorn. Här togs diagram för normaliserad aerodynamisk dämpning och lokal arbetskoefficient fram för olika IBPA (inter-blade phase angle). Detta visade att en IBPA på -90 grader var minst stabil. Icke-stationärt aerodynamiskt arbete utfördes framför allt på rotorbladens ändregioner. S.k. tip-clearance-flöde studerades endast för stationärt flöde.Detta examensarbete ingår delvis i en artikel skriven för European Turbomachinery Conference (ETC). Det verifieras genom jämförelse av de resultat som erhållits från CFX och LUFT (Linearized Unsteady Flow solver for Turbomachinery).

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Topel, Monika. "Improving Concentrating Solar Power Plant Performance through Steam Turbine Flexibility." Doctoral thesis, KTH, Kraft- och värmeteknologi, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-211780.

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The amount of incoming solar energy to earth is greater than any other source. Among existing technologies to harness solar energy there is concentrating solar power (CSP). One advantage of CSP is that is dispatchable, meaning that it can provide power even when the sun is not shining. However, CSP is undergoing challenges which hinder its development such as operating variabilities caused by the fluctuations of the sun or the fact that these systems are not yet cost competitive with respect to other technologies. One way of improving the performance of CSP plants (CSPPs) is by increasing their operational flexibility, specifically their capability for fast starts. In this way it is possible for the CSPP to harness the solar energy as soon as possible, thus producing more energy and increasing its profitability. Over 90% of CSPPs use a steam turbine to generate electricity. Steam turbines are not currently designed with the flexibility required by the CSP application. Steam turbine start-up is limited by thermal stress and differential expansion. If not carefully controlled, these phenomena either consume lifetime or even result in machine failure. The aim of this work was to understand the improvement potential of steam turbine start-up and quantify this in terms of CSPP performance indicators. For this, a thermo-mechanical steam turbine model was developed and validated. The model was then used to analyze potential improvements and thermal constraints to steam turbine start-up operation. Furthermore, a CSP plant techno-economic model was developed including steam turbine details. This modeling approach including two levels of detail allowed for the particularities of the component to be included within the dynamics of the plant and thus be able to connect the perspectives of the equipment manufacturer with those of the plant operator. Reductions of up to 11.4% in the cost of electricity were found in the studies carried out.

QC 20170814

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Zhang, Luying. "Rotating instability on steam turbine blades at part-load conditions." Thesis, University of Oxford, 2013. http://ora.ox.ac.uk/objects/uuid:cf8ecad1-0fd2-49b7-8e28-6d00c62c173e.

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A computational study aimed at improving the understanding of rotating instability in the LP steam turbine last stage working under low flow rate conditions is described in this thesis. A numerical simulation framework has been developed to investigate into the instability flow field. Two LP model turbine stages are studied under various flow rate conditions. By using the 2D simulations as reference and comparing the results to those of the 3D simulations, the basic physical mechanism of rotating instability is analysed. The pressure ratio characteristics across the rotor row tip are found to be crucial to the inception of rotating instability. The captured instability demonstrates a 2D mechanism based on the circumferential variation of unsteady separation flow in the rotor row. The 3D tip clearance flow is found not a necessary cause of the instability onset. Several influential parameters on the instability flow are also investigated by a set of detailed studies on different turbine configurations. The results show that the instability flow pattern and characteristics can be altered by the gap distance between the stator and rotor row, the rotor blading and the stator row stagger angle. Some flow control approaches are proposed based on the observations, which may also serve as design reference. The tip region 3D vortex flow upstream to the rotor row is also captured by the simulations under low flow rate conditions. Its appearance is found to be able to suppress the inception of rotating instability by disrupting the interaction between the rotor separation flow and the incoming flow. Finally, some recommendations for further work are proposed.

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Kadáková, Nina. "Návrh paroplynového zdroje elektřiny." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2020. http://www.nusl.cz/ntk/nusl-417426.

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A combined cycle is one of the thermal cycles used in thermal power plants. It consists of a combination of a gas and a steam turbine, where the waste heat from the gas turbine is used for steam generation in the heat recovery steam generator. The aim of the diploma thesis was the conceptual design of a combined cycle electricity source and the balance calculation of the cycle. The calculation is based on the thermodynamic properties of the substances and the basic knowledge of the Brayton and Rankin-Clausius cycle. The result is the amount and parameters of air, flue gases, and steam/water in individual places and the technological scheme of the source, in which these parameters are listed.

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Wallis, Anne Marjorie. "The control of secondary and leakage flows in a shrouded multistage turbine." Thesis, University of Cambridge, 1997. https://www.repository.cam.ac.uk/handle/1810/272686.

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Jefferson, Marx. "Analysis of combined gas turbine and steam turbine (COGAS) system for marine propulsion by computer simulation." Thesis, University of Newcastle Upon Tyne, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.431133.

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24

Webb, R. A. "Experimental modelling of nucleating and wet steam flows in turbine blading." Thesis, University of Birmingham, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.643570.

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This thesis is concerned with experimental studies of nucleating and wet steam flows over cascades of turbine blading. To simulate conditions in actual turbine flows it is necessary to produce nucleation in sub-sonic flows. has been achieved by the blow-down technique. The classical nucleation theory and the equations describing the growth of droplets are outlined in the literature survey. Application to one- and two-dimensional flows of condensing steam are also given. This is followed by a brief account of the effects of wetness on the flow through turbines.

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25

Gemmell, Brian David. "A consultative expert system for intelligent diagnosis on steam turbine plant." Thesis, University of Strathclyde, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.340915.

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26

CALIANNO, LUCA. "SENSITIVITY STUDIES ON THE THERMAL MODEL OF A SOLAR STEAM TURBINE." Thesis, KTH, Energiteknik, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-192810.

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Förr i tiden, ångturbiner har främst använts för baskraft operation. Numera med den ökade utvecklingen av varierande förnyelsbara är samma ångturbiner motstå högre cykliska operativa system med mer frekvent uppstarter och snabbt föränderliga laster. Som sådan, förbättra den operativa flexibiliteten hos installerade och framtida utformad ångturbiner är en viktig aspekt för att övervägas av utrustning. Ångturbin uppstart är en intressant fas eftersom anses vara den mest intrikata av transienter. Under denna fas kan maskinen potentiellt utsättas för omåttlig termiska spänningar och axiella gnugga på grund av differentiell termisk expansion. Dessa två termiska fenomen antingen konsumera komponent livstid eller kan leda till maskinhaveri om inte kontrolleras noggrant. Som sådan, det finns en balans som skall beaktas mellan ökande turbin uppstart hastighet samtidigt som säker drift och livslängd bevarande av dessa maskiner. För att förbättra den transienta operationer av ångturbiner, blir det viktigt att undersöka deras termiska beteende under uppstarter. För att göra detta, är det viktigt att ha verktyg som kan förutäga den termiska responsen hos maskinen. I denna avhandling fungerar effekterna av olika aspekter och randvillkor om resultaten av ST3M, en KTH internt verktyg, undersöktes med syfte att förstå hur stor blev deras inverkan på sättet att fånga den termiska beteendet hos turbinen i termer av metalltemperatur och differentiell expansion. En industriell högtrycksturbinen validerades mot uppmätta data och genomförs på en känslighetsanalys; denna analys visade att den geometriska approximation införa fel i resultaten, att användningen av empiriska Nusselt korrelationer ge liknande resultat som den validerade modellen och att håligheten antaganden har en stor inverkan på utvecklingen av expansionsskillnaden. Slutligen har en strategi för att validera någon annan liknande turbin till en av studien fallet föreslås för att ge en vägledning för framtida arbeten i hur att validera en modell och vilka är de mest inflytelserika parametrar att ta hand om.
In the past, steam turbines were mostly used for base load operation. Nowadays, with the increased development of variable renewable technologies, these same steam turbines are withstanding higher cyclic operational regimes with more frequent start-ups and fast changing loads. As such, improving the operational flexibility of installed and future designed steam turbines is a key aspect to be considered by equipment manufacturers. Steam turbine start-up is a phase of particular interest since is considered to be the most intricate of transient operations. During this phase, the machine can potentially be subjected to excessive thermal stresses and axial rubbing due to differential thermal expansion. These two thermal phenomena either consume component lifetime or can lead to machine failure if not carefully controlled. As such, there is a balance to be considered between increasing turbine start-up speed while ensuring the safe operation and life preservation of these machines. In order to improve the transient operation of steam turbines, it becomes important to examine their thermal behavior during start-up operation. To do that, it is important to have tools able to predict the thermal response of the machine. In this thesis work the impact of different aspects and boundary conditions on the results of ST3M, a KTH in-house tool, were investigated with the aim of understanding how large was their impact on the way to capture the thermal behavior of the turbine in terms of metal temperature and differential expansion. A small industrial high pressure turbine was validated against measured data and implemented on a sensitivity study; this analysis showed that the geometrical approximation introduce errors in the results, that the use of empirical Nusselt correlations give similar results to the validated model and that the cavity assumptions have a large impact on the trend of the differential expansion. Lastly, a strategy to validate any other similar turbine to the one of the study case was proposed in order to give a guide to future works in how to validate a model and what are the most influent parameters to take care of.

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27

Calianno, Luca. "SENSITIVITY STUDIES ON THE THERMAL MODEL OF A SOLAR STEAM TURBINE." Thesis, KTH, Kraft- och värmeteknologi, 2016. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-193017.

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In the past, steam turbines were mostly used for base load operation. Nowadays, with the increased development of variable renewable technologies, these same steam turbines are withstanding higher cyclic operational regimes with more frequent start-ups and fast changing loads. As such, improving the operational flexibility of installed and future designed steam turbines is a key aspect to be considered by equipment manufacturers. Steam turbine start-up is a phase of particular interest since is considered to be the most intricate of transient operations. During this phase, the machine can potentially be subjected to excessive thermal stresses and axial rubbing due to differential thermal expansion. These two thermal phenomena either consume component lifetime or can lead to machine failure if not carefully controlled. As such, there is a balance to be considered between increasing turbine start-up speed while ensuring the safe operation and life preservation of these machines. In order to improve the transient operation of steam turbines, it becomes important to examine their thermal behavior during start-up operation. To do that, it is important to have tools able to predict the thermal response of the machine. In this thesis work the impact of different aspects and boundary conditions on the results of ST3M, a KTH in-house tool, were investigated with the aim of understanding how large was their impact on the way to capture the thermal behavior of the turbine in terms of metal temperature and differential expansion. A small industrial high pressure turbine was validated against measured data and implemented on a sensitivity study; this analysis showed that the geometrical approximation introduce errors in the results, that the use of empirical Nusselt correlations give similar results to the validated model and that the cavity assumptions have a large impact on the trend of the differential expansion. Lastly, a strategy to validate any other similar turbine to the one of the study case was proposed in order to give a guide to future works in how to validate a model and what are the most influent parameters to take care of.

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28

Burton, Zoe. "Analysis of low pressure steam turbine diffuser and exhaust hood systems." Thesis, Durham University, 2014. http://etheses.dur.ac.uk/10531/.

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This thesis concerns the computational modelling of low pressure (LP) steam turbine exhaust hood flows. A test case for LP last stage blades (LSBs) with a full aerodynamic definition and an accompanying exhaust hood was developed which is representative of current industrial practice. The test case geometry is freely available allowing other researchers to build on this work and is the first of its kind. Studies on this Durham Stage and Exhaust Hood Test Case showed the geometry produces a representative flow pattern and performance metrics comparable to other published research. Using the test case, the effect of condenser cooling water pressure gradient on the hood flow was computed for the first time. A generic boundary condition was developed to represent the transverse condenser cooling water flow and, when applied to the test case, was shown to have a larger influence on the flow asymmetry within the hood than the tip leakage jet. This thesis describes the first application of the non-linear harmonic (NLH) method to couple the LSBs to the exhaust hood. This method enabled the circumferential non-uniformity which develops in the exhaust hood to be transferred across the interface to the stage, in half the computational demand of the full annulus frozen rotor approach. The first review of the influence of inlet circumferential asymmetry on the hood flow field highlighted that modelling its effect is not as crucial as indicated in the literature, unless the diffuser axial length is very compact or if off-design flows are to be studied. A series of recommendations and guidelines for the CFD modelling of steam turbine exhaust hood flows based on this work are supplied. Experimental validation of the Durham Stage and Exhaust Hood Test Case and a comparison of full unsteady studies with the NLH method should be the next steps in this research.

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29

Iredale, Peter David. "Investigation into unsteady valve flow in steam turbine inlet governing valves." Thesis, University of Leicester, 2000. http://hdl.handle.net/2381/30179.

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When partially closed, steam turbine governing valves rely on flow separation from the valve head and seat to generate loss and throttle the flow. The aim of this type of valve is to avoid separation and therefore eliminate loss when the valve is fully open, and to have stable and controllable separations at all other valve lifts. Any significant unsteadiness in the valve flow can result in unacceptable mechanical vibration of the valve, which in extreme cases can lead to failure. Results will be discussed from work that has been undertaken into valve flow instabilities at Leicester University Engineering Department in collaboration with Alstom Energy Ltd. At high lifts, the Mach number of the steam flow between the head and the seat is sufficiently low for the fluid to be considered as incompressible. Water was therefore used as the working fluid in the tests at Leicester to model accurately the flow in a fifth scale acrylic model valve under high lift conditions. Results from laser light sheet visualisation, Particle Image Velocimetry and transient pressure measurements of the valve flow are presented. Laser light sheet illumination and high-speed Cine photography have been used to visualise the highly three dimensional valve flow. A range of valve head geometries has been tested. The results of the flow visualisation show the presence of stable and unstable separation zones and their influence on the valve flow. Particle Image Velocimetry has provided quantitative information on these features. Methods for stabilising the separation zones by modifying the valve head and seat have also been investigated and the results from these tests have shown improvements in reducing valve exit pipe unsteadiness.

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30

Jannesson, Ann. "Redesign of Steam Strainer." Thesis, Linköping University, Department of Management and Engineering, 2008. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-10534.

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This thesis was done at Siemens Industrial Turbomachinery AB in Finspång.

Placed in the inlet to a steam turbine is a filter, a steam strainer, which separates particles and larger objects from the steam. These particles and objects will cause solid particle erosion in the actual turbine if they pass by. The strainer is exposed to large pressure drops when clogged, i.e., static loads which require a good creep resistance in the material. The temperature of the steam in the turbines is increased in order to deliver more energy; today’s turbines are dimensioned for almost 600°C. The material in parameters, such as the strainer, should also be adjusted to the higher temperatures. Today’s temperature is suspected to be the cause of damage in the strainer because the present material might get brittle at higher temperatures.

The purpose of the thesis is to find a new material for the strainers and also to find a new concept for how to manufacture them. There are nine sizes of steam strainers but only five of them are exposed to the highest temperatures and pressure drops, which make only these five interesting to examine in this thesis.

The concepts were chosen according to the method of Ulf Liedholm (1999), Systematic Concept Development. The thesis did not end up with only one concept because not all possible methods were tested but the suggestions are all based on a strainer built out of membranes as before. The discussed methods to join the membranes are EB-welding, laser welding and brazing.

An investigation to find if it was possible to improve the strength of the strainer by simple design changes and a calculation of what percentage of clogging the strainer would hold for was also done.

The chosen material was a creep resistant, alloy special steel. Three suggestions on concepts were presented. The improvements in strength from simple changes in design were too small and too costly but are enclosed as an appendix in this report. Calculations on the strength were done without regard taken to fatigue caused by possible vibrations, so-called high cycle fatigue.

What would be interesting to do as a future work based on this thesis is, of course, to test the three manufacturing methods and evaluate them thoroughly but also to discuss other ways of improving the strength through design changes. These should be done regarding the flow. Also high cycle fatigue should be considered.

Examensarbetet utfördes i Finspång på Siemens Industrial Turbomachinery AB.

I inloppet till en ångturbin sitter ett filter, en ångsil, som silar bort partiklar och större föremål från ångan. Dessa partiklar och föremål skadar turbinen genom erosion om de tillåts passera. Ångsilen i sig utsätts för stora tryckfall när den blir igensatt, vilket kräver god krypresistans i materialet. För att kunna leverera allt mer energi utvecklas ångturbiner som kan arbeta vid allt högre ångtemperaturer. De som konstrueras idag dimensioneras för närmare 600 °C. Då måste även materialet i detaljer, som silen, anpassas. De temperaturer som används idag misstänks vara en orsak till skador på silarna eftersom nuvarande material kan bli sprött då temperaturen stiger.

Syftet med arbetet är att välja ett nytt material till ångsilarna samt att finna nya koncept för hur ångsilen kan tillverkas. Nio storlekar på ångsilar finns men bara fem av dessa används vid högsta temperatur och tryck och därför har enbart dessa fem använts vid beräkningar i detta examensarbete.

Koncept valdes enligt Liedholms (1999) metod, Systematisk Konceptutveckling. Istället för ett slutligt koncept lämnas istället tre förslag. Detta görs då de olika förslagen inte har testats ordentligt. Samtliga tre förslag är baserade på den typen av sil uppbyggd av membran som används idag men med nya metoder att sammanfoga membranen med. Metoderna är EB-svetsning, lasersvetsning och vakuumlödning.

En undersökning om det var ekonomiskt rimligt att förbättra hållfastheten genom enkla designändringar samt en beräkning över hur stor igensättning silen klarar gjordes.

Materialet som valdes var ett krypresistant, legerat specialstål. De tre förslagen på koncept lades fram. Designändringarna gav inte det resultat som det hade hoppats på och var framförallt för dyra att genomföra. Hållfasthetsberäkningar gjordes utan hänsyn till utmattning på grund av eventuella vibrationer, så kallad högcykelutmattning.

Som framtida arbete med detta examensarbete som språngbräda rekommenderas i första hand att testa de föreslagna metoderna för sammanfogning av membranen men även djupare diskussioner kring hur hållfastheten skulle kunna förbättras genom designförändringar borde tas. Dessa skulle kunna genomföras med avseende på flödet. Även högcykelutmattning, HCF, borde undersökas.

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31

Skillings, S. A. "An analysis of the condensation phenomena occurring in wet steam turbines." Thesis, Open University, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.380667.

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32

Kysel, Stanislav. "Energetický paroplynový zdroj na bázi spalování hutnických plynů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2012. http://www.nusl.cz/ntk/nusl-230245.

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The main goal of my thesis is to carry out thermic calculations for adjusted conditions of electric and heat energy consumption. The power of the generator is 330 MW. In the proposal, you can find combustion trubines type GE 9171E. Steam-gas power plant is designed to combust metallurgical gases. Effort of the thesis focuses also on giving a new informations about trends in combinated production of electric and heat energy.

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Kysel, Stanislav. "Energetický paroplynový zdroj na bázi spalování hutnických plynů." Master's thesis, Vysoké učení technické v Brně. Fakulta strojního inženýrství, 2011. http://www.nusl.cz/ntk/nusl-229801.

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The main goal of my thesis is to carry out thermic calculations for adjusted conditions of electric and heat energy consumption. The power of the generator is 330 MW. In the proposal, you can find combustion trubines type GE 9171E. Steam-gas power plant is designed to combust metallurgical gases. Effort of the thesis focuses also on giving a new informations about trends in combinated production of electric and heat energy.

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34

Mohammed, Riadh Abdulla. "The growth of fatigue cracks in a turbine shaft steel under mixed mode I and III." Thesis, University of Sheffield, 1994. http://etheses.whiterose.ac.uk/14799/.

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35

Mamat, Zainul Asri. "The performance of a cascade of nozzle turbine blading in nucleating steam." Thesis, University of Birmingham, 1996. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.643566.

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The thesis describes an experimental investigation of nucleating flows of steam in a cascade of nozzle turbine blading. To obtain nucleation in subsonic flows of steam, a supercooled supply is necessary which has been achieved under blow-down conditions. The literature survey covers the early investigations of condensation in flowing steam, the development of nucleation theory, droplets growth laws and their simple applications in the study of phenomena associated with condensation in nozzles. Finally some of the problems associated with wetness in turbines are considered. Next the experimental facility is described. The facility is a blow-down steam tunnel constructed for the study of two-dimensional two-phase flows. The instrumentation caters for the measurements of surface pressure distributions, wake traverses downstream of the cascade as well as for the optical observations and droplet size measurements. The main experimental chapter includes the results of the surface pressure measurements, wake traverses downstream of the cascade, flow observations and droplet size measurements. Some measurements of the thermodynamic nucleation losses are also presented together with the calibration of the probe used for the wake traverses. Comparisons of results under steam superheated and nucleating flows reveal the blades to have different characteristics when the outlets have been supersonic or sonic. The most notable difference has been the pressure rise associated with the zone of rapid condensation, its location and its insensitivity to changes in inlet temperatures and overall pressure ratios. In contrast, when the outlet has been subsonic, the blades exhibit similar characteristics under steam superheated and nucleating conditions. In addition, comparisons made with the results obtained previously by other investigators using different blades suggest that the interaction between the zone of rapid condensation and the aerodynamic performance of the blades can vary depending on the blade shape.

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36

Ahmad, Mansoor. "Experimental assessment of droplet impact erosion of low pressure steam turbine blades." Aachen Shaker, 2009. http://d-nb.info/998626953/04.

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37

Ababatin, Yasser. "RECOVERY OF EXHAUST WASTE HEAT FOR A HYBRID CAR USING STEAM TURBINE." OpenSIUC, 2015. https://opensiuc.lib.siu.edu/theses/1653.

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A number of car engines operate with an efficiency rate of approximately 22% to 25% [1]. The remainder of the energy these engines generate is wasted through heat escape out of the exhaust pipe. There is now an increasing desire to reuse this heat energy, which would improve the overall efficiency of car engines by reducing their consumption of fuel. Another benefit is that such reuse would minimize harmful greenhouse gases that are emitted into the environment. Therefore, the purpose of this project is to examine how the wasted heat energy can be reused and/or recovered by use of a heat recovery system that would store this energy in a hybrid car battery. Green turbines will be analyzed as a possible solution to recycle the lost energy in a way that will also improve the overall automotive energy efficiency.

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38

Guilliams, Hunter Benjamin. "Investigation of Aerodynamic Profile Losses for a Low-Reaction Steam Turbine Blade." Thesis, Virginia Tech, 2014. http://hdl.handle.net/10919/54578.

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This thesis presents the results of a linear cascade experiment performed on the mean-line and near-tip sections of a low-reaction steam turbine blade and compares them to CFD of the former. The purpose of these tests was the refinement of a proprietary empirical profile loss model. A review of the literature shows that experimental data on this type of blade is not openly available. The continued efficacy of empirical loss models to low-reaction steam turbine blades requires data from experiments such as the present study. Tests covered a range of incidence from -6 to +4 and exit Mach numbers from 0.4 to 0.6. Extensive static pressure taps on the blades allowed detailed examinations of blade loading. This loading was dissimilar to steam turbine blade loading in the open literature. A traversing five-hole probe measured conditions downstream of the blade row to enable the calculation of a total pressure loss coefficient. The area-averaged total pressure loss coefficient for both profiles was near 0.08 and was not sensitive to incidence or exit Mach number over the ranges tested.
Master of Science

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39

Verona, Claire L. "Stress corrosion cracking of low pressure steam turbine blade and rotor materials." Thesis, Loughborough University, 2012. https://dspace.lboro.ac.uk/2134/10165.

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Stress corrosion cracking of a 14 wt% Cr martensitic stainless steel, with commercial names PH-15Cr5Ni, FV520B or X4CrNiCuMo15-5, used for the manufacture of low pressure turbine blades, has been studied with the intention of gaining a better understanding of the processes involved, how they occur and why. Industrially this is very important as stress corrosion cracking is considered to be a delayed failure process, whereby microscopic cracks can potentially propagate through a metal undetected until catastrophic failure occurs. The aim of this work is to establish links between crack length and external factors, such as exposure time, in order to devise a method of dating stress corrosion cracks and therefore predicting their possible occurrence in-service.

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40

Newby, Mark. "Optimisation of shot peening for 12Cr steel in steam turbine blade applications." Thesis, University of Plymouth, 2013. http://hdl.handle.net/10026.1/1493.

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Power generation in thermal stations typically relies on large steam turbines. The corrosion resistant steel blades used in the last stage of a typical low pressure rotor set are approximately 1m long and experience high centrifugal loading during service. They operate in a wet steam environment, at approximately 60°C while rotating at 3000rpm, and failure modes include high and low cycle fatigue, stress corrosion cracking or corrosion fatigue. The blades are retained by a fir tree root which is normally shot-peened to generate compressive residual stresses that resist crack initiation. Finite element (FE) modelling has indicated that, in the absence of shot-peening, stresses above yield are induced at the fir tree root during operation. In a shot-peened blade these lead to relaxation of the shot peening residual stresses. To date, no systematic information has been obtained on the level of residual stresses induced in the fir tree by shot-peening and their subsequent relaxation during service loading, nor are there any guidelines as to the magnitude of residual stresses necessary to ensure integrity of the turbine over a life span of at least twenty years. At least one of these blades has suffered catastrophic failure in recent years causing severe damage, in excess of €100M, to the turbine-generator set on a South African power station [1]. This thesis reports results from a comprehensive program of residual stress measurements at the shot-peened fir tree roots of service blades, and in specimens that simulate the root conditions, using diffraction data from laboratory and synchrotron X-ray radiation (SXRD). Shot-peening coverage between 75% and 200% was used and stresses were measured over a depth of 5mm into the blades/specimens. Measurements were made in the as-peened condition and after applying cyclic stresses representative of overspeed proof testing and of service operation. The results were used to calibrate FE modelling of residual stresses and as input into fatigue life prediction.

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41

Broadbent, Tristram. "The effect of the interaction between wear and steam oxidation on the degradation of abradable seals for steam turbine applications." Thesis, University of Leicester, 2015. http://hdl.handle.net/2381/32238.

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The following report investigates the use of abradable seal technology in industrial steam turbine applications. Abradable seals are a highly adaptable, widely applicable and cheap method of improving seal performance. By retrofitting abradable coatings to existing labyrinth seals, improvements in the range of 0.5% - 1% power output are seen with cost returns within two years [1]. The intention of this investigation was to develop fundamental understanding of the seal degradation process. A Multi Oxidation and Incursion Steam Test (MOIST) rig was designed from concept, through detailed design and finally commissioned. During commissioning the capabilities of the MOIST rig were defined. Although flowing steam operation was not achieved during this investigation, a theoretically proofed steam system is in place for future development. High temperature operation was achieved, although not reliably. Reliable, repeatable atmospheric tests were developed, representative of the start-up and shut-down operations of an industrial steam turbine. These tests produced relative velocities up to 121ms-1 between coatings and blades, and incursion rates up to 50μms-1. ST12T, Nimonic 80A and Nimonic 101 blade materials were tested against a bentonite-NiCrAl abradable coating. The results suggest that the bentonite-NiCrAl abradable coating tested was highly suitable as an abradable coating for all blade materials. Additionally, high temperature tests are necessary to fully prove the use of blade materials against coating systems. Simultaneously, non-MOIST rig oxidation testing was performed in the range of 580˚C - 800˚C in static air and 580˚C in flowing steam for exposure times up to 5000 hrs. Bentonite-NiCrAl top coat - NiAl bond coat and either a STG-9T or IN625 substrate were analysed to devise mechanistic models for the oxidation of the top coat, bond coat, substrate and all associated interfaces. It was concluded that steam oxidation is intrinsically different to air oxidation and that adapting the bond coat to include Cr would significantly improve the oxidation resistance and service life of the coating system investigated.

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42

Vytla, Veera Venkata Sunil Kumar. "CFD Modeling of Heat Recovery Steam Generator and its Components Using Fluent." UKnowledge, 2005. http://uknowledge.uky.edu/gradschool_theses/336.

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Combined Cycle power plants have recently become a serious alternative for standard coal- and oil-fired power plants because of their high thermal efficiency, environmentally friendly operation, and short time to construct. The combined cycle plant is an integration of the gas turbine and the steam turbine, combining many of the advantages of both thermodynamic cycles using a single fuel. By recovering the heat energy in the gas turbine exhaust and using it to generate steam, the combined cycle leverages the conversion of the fuel energy at a very high efficiency. The heat recovery steam generator forms the backbone of combined cycle plants, providing the link between the gas turbine and the steam turbine. The design of HRSG has historically largely been completed using thermodynamic principles related to the steam path, without much regard to the gas-side of the system. An effort has been made using resources at both UK and Vogt Power International to use computational fluid dynamics (CFD) analysis of the gas-side flow path of the HRSG as an integral tool in the design process. This thesis focuses on how CFD analysis can be used to assess the impact of the gas-side flow on the HRSG performance and identify design modifications to improve the performance. An effort is also made to explore the software capabilities to make the simulation an efficient and accurate.

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43

Dechamps, P. J. Th. "Technical and economical considerations on repowering a steam cycle with a gas turbine." Thesis, Cranfield University, 1990. http://hdl.handle.net/1826/3478.

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There is a growing interest in the use of combined cycles for power generation. These cycles are known to have economical advantages over classical steam cycles under some circumstances. This thesis looks at the implications of topping a existing steam cycle with one or more gas turbines. After a short overview of combined cycles, the various options available for repowering are presented and discussed. The number of feasible basic options is reduced to two by considering technical issues related to classical steam cycles. A computer code that was developed to analyze the design point as well as the off design performance of repowered configurations is then presented. Design point performance examples show what can be achieved by repowering, and how it compares with genuine combined cycles. Off design performance examples illustrate how the off design behaviour can be improved by special gas turbine features and arrangements. An economic analysis method based on cash flow predictions and sensitivity analysis is developed and illustrated on two typical situations. Throughout the work, the emphasis is put on the necessary integration of technical and economical analysis for decision making.

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44

Fuhrer, Christopher [Verfasser]. "Numerical Investigation on Spontaneous Condensation in Low-Pressure Steam Turbine Aeroelasticity / Christopher Fuhrer." Düren : Shaker, 2021. http://d-nb.info/1238497632/34.

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45

Batista, Julio Cesar [UNESP]. "Microgeração de energia eletrica (abaixo de 100kw) utilizando turbina tesla modificada." Universidade Estadual Paulista (UNESP), 2010. http://hdl.handle.net/11449/106422.

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Este trabalho desenvolve um sistema para gerar energia elétrica com caldeira e turbina, para ocupar um nicho de mercado em que os sistemas a vapor existentes não são economicamente viáveis. O sistema utiliza a turbina Tesla que é compatível para essa faixa e não possui pás, podendo operar com vapor saturado fornecido por uma pequena caldeira consumindo lenha. A micro-geração proposta pode levar energia a milhões de brasileiros no campo, onde se dispõe de algum tipo de biomassa. Apesar do baixo custo da turbina Tesla, por ser de simples construção e compacta, e de suas incontáveis possibilidades de aplicação, se desconhece, até então, aplicações comerciais massivas devido ao baixo torque obtido nos protótipos feitos desde 1910 e por essa razão foi modificada. Este trabalho inova ao desenvolver um protótipo da turbina Tesla modificado para fornecer maior torque e ao comparar à turbina Tesla original. Devido à inexistência de equações que descrevem a turbina Tesla, um modelo matemático que permite projetar a turbina Tesla foi desenvolvido e validado por resultados experimentais e de simulação. Testes comparativos com duas turbinas com as mesmas dimensões mostraram que a turbina Tesla modificada apresentou eficiência superior à turbina Tesla original. Desenvolveu-se, também, um protótipo do sistema para micro-geração utilizando a turbina Tesla modificada, caldeira e gerador elétrico. Os custos do sistema e da energia gerada foram comparados com os de outros meios de geração mostrando serem competitivos economicamente para essa faixa de operação.
This work develops a system to generate electric power with boiler and turbine that aims to occupy the niche of the market for which steam systems are not economically viable. The system uses a Tesla turbine, which is compatible to the range of power. Also, it does not have blades, being able to operate with steam delivered by a small boiler fed with wood. The proposed micro-generation system can take energy to millions of Brazilians living in the country, where some type of biomass is available. In despite of the low cost of the Tesla turbine, because it is compact and simple to build, and despite of its uncountable possibilities of applications, massive commercial applications of the technology are not found due to the low torque of the prototypes built since 1910. For this reason, the Tesla turbine was modified. This work is original since it develops a modified Tesla turbine prototype to furnish a higher torque when compared to an original Tesla turbine. Due to the lack of equations that model a Tesla turbine, a mathematical model was developed to allow the design of the Tesla turbine; it was validated by means of experimental and simulating results. The comparative tests with two turbines, with same dimensions, showed that the modified Tesla turbine presents a higher efficiency than the original Tesla turbine. A micro-generation system, using the modified Tesla turbine, boiler and electric generator, was also developed. The costs of the system and of the generated energy were compared with other means of generation and showed to be commercially competitive for that range.

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Hartigan, Timothy James. "Effects of notches and fretting on fatigue of steam turbine materials at 524°C." Thesis, Georgia Institute of Technology, 2002. http://hdl.handle.net/1853/16726.

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Łuczyński, Piotr [Verfasser]. "Warm-keeping and Pre-warming of a Steam Turbine Using Hot Air / Piotr Łuczyński." München : Verlag Dr. Hut, 2020. http://d-nb.info/1219471208/34.

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Ahmad, Mansoor [Verfasser]. "Experimental assessment of droplet impact erosion of low-pressure steam turbine blades / Mansoor Ahmad." Aachen : Shaker, 2009. http://d-nb.info/1161302182/34.

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He, Binyan. "Fatigue crack growth behaviour in a shot peened low pressure steam turbine blade material." Thesis, University of Southampton, 2015. https://eprints.soton.ac.uk/388077/.

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Chu, Teik Lin. "Effects of Mach Number and Flow Incidence on Aerodynamic Losses of Steam Turbine Blades." Thesis, Virginia Tech, 1997. http://hdl.handle.net/10919/10093.

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Abstract:

An experiment was conducted to investigate the aerodynamic losses of two high-pressure steam turbine nozzles (526A, 525B) subjected to a large range of incident angle and exit Mach number. The blades were tested in a 2D transonic windtunnel. The exit Mach number ranged from 0.60 to 1.15 and the incidence was varied from -34o to 35o. Measurements included downstream Pitot probe traverses, upstream total pressure, and endwall static pressures. Flow visualization techniques such as shadowgraph photography and color oil flow visualization were performed to complement the measured data. When the exit Mach number for both nozzles increased from 0.9 to 1.1, the total pressure loss coefficient increased by a factor of 7 as compared to the total pressure losses observed at subsonic condition (M2<0.9). For the range of incidence tested, the effect of flow incidence on the total pressure losses is less pronounced. Based on shadowgraphs taken during the experiment, it's believed that the large increase in losses at transonic conditions is due to strong shock/boundary layer interaction that may lead to flow separation on the blade suction surface. From the measured total pressure coefficients, a modified loss model that accounts for higher losses at transonic conditions was developed. The new model matches the data much better than the existing Kacker-Okapuu model for transonic exit conditions.
Master of Science

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