Journal articles: 'Compressor optimisation'

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Beckers, Jarl, Diederik Coppitters, Ward De Paepe, Francesco Contino, Joeri Van Mierlo, and Björn Verrelst. "Multi-Fidelity Design Optimisation of a Solenoid-Driven Linear Compressor." Actuators 9, no. 2 (May 11, 2020): 38. http://dx.doi.org/10.3390/act9020038.

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Improved management and impermeability of refrigerants is a leading solution to reverse global warming. Therefore, crank-driven reciprocating refrigerator compressors are gradually replaced by more efficient, oil-free and hermetic linear compressors. However, the design and operation of an electromagnetic actuator, fitted on the compression requirements of a reciprocating linear compressor, received limited attention. Current research mainly focuses on the optimisation of short stroke linear compressors, while long stroke compressors benefit from higher isentropic and volumetric efficiencies. Moreover, designing such a system focuses mainly on the trade-off between number of copper windings and the current required, due to the large computational cost of performing a full geometric design optimisation based on a Finite Element Method. Therefore, in this paper, a computationally-efficient, multi-objective design optimisation for six geometric design parameters has been applied on a solenoid driven linear compressor with a stroke of 44.2 mm. The proposed multi-fidelity optimisation approach takes advantage of established models for actuator optimisation in mechatronic applications, combined with analytical equations established for a solenoid actuator to increase the overall computational efficiency. This paper consists of the multi-fidelity optimisation algorithm, the analytic model and Finite Element Method of a solenoid and the optimised designs obtained for optimised power and copper volume, which dominates the actuator cost. The optimisation results illustrate a trade-off between minimising the peak power and minimising the volume of copper windings. Considering this trade-off, an intermediate design is highlighted, which requires 33.3% less power, at the expense of an increased copper volume by 5.3% as opposed to the design achieving the minimum copper volume. Despite that the effect of the number of windings on the input current remains a dominant design characteristic, adapting the geometric parameters reduces the actuator power requirements significantly as well. Finally, the multi-fidelity optimisation algorithm achieves a 74% reduction in computational cost as opposed to an entire Finite Element Method optimisation. Future work focuses on a similar optimisation approach for a permanent magnet linear actuator.

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Goryachkin, E. S., V. N. Matveev, G. M. Popov, O. V. Baturin, and Yu D. Novikova. "Optimisation Method for Multistage Compressors." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 3 (138) (September 2021): 38–59. http://dx.doi.org/10.18698/0236-3941-2021-3-38-59.

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The paper presents an algorithm for seeking an optimal blade configuration for multistage axial-flow compressors. The primary tool behind the algorithm is 3D CFD simulation, augmented by commercial optimisation software. The core of the algorithm involves feeding an initial data vector to the parametric simulation module so as to form a "new" blade geometry, which is then transferred to 3D computational software. The results obtained are further processed in a program that implements the algorithm for seeking the optimum and forms a new input data vector to achieve the set goal. We present a method of parametrically simulation the blade shape, implemented in a software package, making it possible to describe the shape of the compressor blade profiles using a minimum number of variables and to automatically change the shape in the optimisation cycle. The algorithm developed allows the main parameters of compressor operation (efficiency, pressure ratio, air flow rate, etc.) to be improved by correcting the profile shape and relative position of the blades. The algorithm takes into account various possible constraints. We used the method developed to solve practical problems of optimising multistage axial compressors of gas turbine engines for various purposes, with the number of compressor stages ranging from 3 to 15. As a result, the efficiency, pressure ratio and stability margin of gas turbine engines were increased

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Cyklis, Piotr, and Przemysław Młynarczyk. "An innovative simulation method for the estimation of the nozzle pressure pulsation attenuation." Journal of Vibration and Control 23, no. 16 (December 13, 2015): 2690–703. http://dx.doi.org/10.1177/1077546315619534.

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Pressure pulsations in volumetric compressor manifolds have a high impact on compression power requirement and the reliability of manifold operation. These pulsations induce vibrations, noise, and in some cases, mechanical failure of piping or compressor valves. For pressure pulsation attenuation, different types of mufflers are applied using a design based upon the Helmholtz resonator approach. This design is particularly effective for constant revolution speed compressors. For contemporary applications of variable revolution speed compressors, other pressure pulsation attenuation methods are needed. It is known that different shapes of nozzles can attenuate pressure pulsations, however, they unfortunately increase the compressor power at the same time. The main criterion for nozzle selection is achieving pressure pulsation attenuation that is as high as possible whilst having the lowest possible effect on compressor power. In this paper, innovative computational fluid dynamics (CFD) simulation methodology is applied for the optimisation of nozzle shape and size. The steady flow simulation results correspond with compressor power consumption and impulse flow simulation results are related to pressure pulsation attenuation. This method has been validated on the basis of the experimental results for three different nozzle geometries. For experimental validation, nozzles have been mounted in the variable speed screw compressor discharge manifold.

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Xu, Cheng, and Ryoichi S. Amano. "Empirical Design Considerations for Industrial Centrifugal Compressors." International Journal of Rotating Machinery 2012 (2012): 1–15. http://dx.doi.org/10.1155/2012/184061.

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Computational Fluid Dynamics (CFD) has been extensively used in centrifugal compressor design. CFD provides further optimisation opportunities for the compressor design rather than designing the centrifugal compressor. The experience-based design process still plays an important role for new compressor developments. The wide variety of design subjects represents a very complex design world for centrifugal compressor designers. Therefore, some basic information for centrifugal design is still very important. The impeller is the key part of the centrifugal stage. Designing a highly efficiency impeller with a wide operation range can ensure overall stage design success. This paper provides some empirical information for designing industrial centrifugal compressors with a focus on the impeller. A ported shroud compressor basic design guideline is also discussed for improving the compressor range.

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Najjaran, Ahmad, Saleh Meibodi, Zhiwei Ma, Huashan Bao, and Tony Roskilly. "Experimentally Validated Modelling of an Oscillating Diaphragm Compressor for Chemisorption Energy Technology Applications." Energies 16, no. 1 (January 2, 2023): 489. http://dx.doi.org/10.3390/en16010489.

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This study presents a detailed dynamic modelling and generic simulation method of an oscillating diaphragm compressor for chemisorption energy technology applications. The geometric models of the compressor were developed step by step, including the diaphragm movement, compressor dimensions, chamber areas and volumes and so on. The detailed mathematical model representing the geometry and kinematics of the diaphragm compressor was combined with the motion equation, heat transfer equation and energy balance equation to complete the compressor modelling. This combination enables the novel compressor model to simultaneously handle the simulation of momentum and energy balance of the diagram compressor. Furthermore, an experimental apparatus was set up to investigate and validate the present modelling and the simulation method. The performance of the compressor was experimentally evaluated in terms of the mass flow rate of the compressor at various compression ratios. Additionally, the effects of different parameters such as the inlet temperature and ambient temperature at various compressor ratios on the compressor performance were investigated. It was found reducing the inlet temperature from 40 to 5 °C at a constant pressure results in the enhancement of the compressor flow rate up to 14.7%. The compressor model proposed and developed in this study is shown to be not only able to accurately deal with the complexity of the dynamic behaviour of the compressor working flow but is also capable of effectively representing diaphragm compressors for analysis and optimisation purposes in various applications.

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Basha, Nausheen, Ahmed Kovacevic, and Sham Rane. "Analysis of Oil-Injected Twin-Screw Compressor with Multiphase Flow Models." Designs 3, no. 4 (December 16, 2019): 54. http://dx.doi.org/10.3390/designs3040054.

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Growing demands for energy are motivating researchers to conduct in-depth analysis of positive displacement machines such as oil-injected screw compressors which are frequently used in industrial applications like refrigeration, oil and gas and air compression. The performance of these machines is strongly dependent on the oil injection. Optimisation of oil has a great energy saving potential by both increasing efficiency and reducing other impacts on the environment. Therefore, a three-dimensional, transient computational fluid dynamics study of oil injection in a twin-screw compressor is conducted in this research. This study explores pseudo single-fluid multiphase (SFM) models of VOF (Volume of Fluid) and a mixture for their capability to predict the performance of the oil-injected twin screw compressor and compare this with the experimental values. SCORGTM (Screw Compressor Rotor Grid Generator) is used to generate numerical grids for unstructured solver Fluent with the special interface developed to facilitate user defined nodal displacement (UDND). The performance predictions with both VOF and mixture models provide accurate values for power consumption and flow rates with low deviation between computational fluid dynamics (CFD) and the experiment at 6000 RPM and 7.0 bar discharge pressure. In addition, the study reflects on differences in predicting oil distribution with VOF, mixture and Eulerian-Eulerian two-fluid models. Overall, this study provides an insight into multiphase flow-modelling techniques available for oil-injected twin-screw compressors comprehensively accounting for the details of oil distribution in the compression chamber and integral compressor performance.

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Chen, Q. J., and K. T. Ooi. "Geometric Optimisation of a Coupled Vane Compressor." IOP Conference Series: Materials Science and Engineering 1180, no. 1 (September 1, 2021): 012028. http://dx.doi.org/10.1088/1757-899x/1180/1/012028.

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Gallar, Luis, Manuel Arias, Vassilios Pachidis, and Riti Singh. "Stochastic axial compressor variable geometry schedule optimisation." Aerospace Science and Technology 15, no. 5 (July 2011): 366–74. http://dx.doi.org/10.1016/j.ast.2010.08.010.

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Kumar, A., A. Kovacevic, S. A. Ponnusami, S. Patil, S. Abdan, and N. Asati. "On performance optimisation for oil-injected screw compressors using different evolutionary algorithms." IOP Conference Series: Materials Science and Engineering 1267, no. 1 (November 1, 2022): 012021. http://dx.doi.org/10.1088/1757-899x/1267/1/012021.

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Energy consumed for pressurizing air makes a significant proportion of total electrical energy consumption worldwide. To reduce the carbon footprint, it is necessary to have air compressors, which can operate efficiently over a large range of pressures and flow including full load and part load conditions. Several studies have been performed in this area including some which monitor the performance of a large number of compressors to develop strategies for their designs. This paper focuses on the design optimisation of geometrical and oil parameters of oil-injected screw compressors using different evolutionary algorithms such as genetic algorithm (GA), covariance matrix adaptation evolution strategy (CMA-ES), and so on. A comparison of the performance of these algorithms is presented. SCORG and GT-SUITE (commercial software tools for screw compressor thermodynamic simulations and optimisation) are used in the integrated model producing promising results. Feasibility of the optimum outcomes generated by these algorithms is critically evaluated from machine and system design point of view. Finally, in the context of optimisation presented here, the simplex converges fastest as compared to other algorithms. In the future study, the system design limitations are to be incorporated as constraints for the optimisation along with the objective to improve energy efficiency.

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Natig Abbasov, Natig Abbasov, and Eldar Umudov Eldar Umudov. "DESIGN OF CENTRIFUGAL COMPRESSOR IMPELLER FOR OPTIMAL EFFICIENCY." ETM - Equipment, Technologies, Materials 09, no. 01 (January 22, 2022): 121–30. http://dx.doi.org/10.36962/etm09012022121.

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A new methodology is proposed to use comprehensive up-to-date commercial software tools for Heat Exchanger Network (HEN) reliability modelling and optimisation. The idea behind this proposal is that to apply the combination of specific HEN optimisation and reliability software packages has several advantages over the commonly used approach. There is a variety of features that need to be taken into account to choose the right software tool. The HEN design has a significant impact on reliability issues and this should be considered. There are many related issues and features - the robustness, the type of welding, the increment of maximum mechanical resistance, the impact on manufacturing costs, reduction of lost opportunity costs caused by exchanger outages, troubleshooting of heating exchanger problems by operators etc. Fouling should be analysed as it has a significant impact on maintenance issues. Up to 30 % decrease of maintenance costs can be achieved annually by applying advanced reliability results and determining heat exchanger failure causes. These analyses include the investigation of failure causes, prediction of future probabilities of failures, cleaning planning and scheduling and the calculation of reliability and maintainability. Keywords: heat exchangers, modelling and optimisation, design of network, oil refinery, heat recovery systems.

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Blinov, Vitalii, Viacheslav Sedunin, and Oleg Komarov. "Multi-criteria optimisation of subsonic axial compressor blading." IOP Conference Series: Materials Science and Engineering 643 (November 13, 2019): 012133. http://dx.doi.org/10.1088/1757-899x/643/1/012133.

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HANTSCHK, Carl Christian, and Marco GEISLER. "Challenges in delivering effective noise management at gas compressor stations." INTER-NOISE and NOISE-CON Congress and Conference Proceedings 265, no. 5 (February 1, 2023): 2793–800. http://dx.doi.org/10.3397/in_2022_0391.

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The basic principles applied in gas compressor stations to manage noise and demonstrate compliance with statutory acoustic requirements are not different from those used with most other industrial activities. Well-known and proven standard procedures involve sound emission assessment, acoustic modeling, model verification, development of a noise control concept and its optimisation until compliance can be demonstrated. However, noise control for some of the typical equipment in gas compression is extremely demanding in terms of both acoustic and operational/safety aspects so that it requires special attention. Examples are the exhausts of the gas turbines driving the compressors and the extensive network of gas piping. Because of their high and strongly varying sound emissions the exhausts pose a significant challenge in designing effective silencers. In addition, flow-generated self-noise in the silencers is a risk that needs to be avoided. For the piping sound attenuation by acoustic lagging is in conflict with corrosion and maintenance/accessibility problems and makes an optimised lagging concept an ambitious task. The present contribution illustrates typical problems encountered and possibilities to deal with them. It is based on data and experiences with gas compressor stations with very stringent acoustic requirements.

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Mustaffa, Ahmad Fikri, and Vasudevan Kanjirakkad. "Stall margin improvement in a low-speed axial compressor rotor using a blockage-optimised single circumferential casing groove." Journal of the Global Power and Propulsion Society 5 (May 3, 2021): 79–89. http://dx.doi.org/10.33737/jgpps/133912.

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The stall margin of tip-critical axial compressors can be improved by using circumferential casing grooves. From previous studies, in the literature, the stall margin improvement due to the casing grooves can be attributed to the reduction of the near casing blockage. The pressure rise across the compressor as the compressor is throttled intensifies the tip leakage flow. This results in a stronger tip leakage vortex that is thought to be the main source of the blockage. In this paper, the near casing blockage due to the tip region aerodynamics in a low-speed axial compressor rotor is numerically studied and quantified using a mass flow-based blockage parameter. The peak blockage location at the last stable operating point for a rotor with smooth casing is found to be at about 10% of the tip chord aft of the tip leading edge. Based on this information, an optimised single casing groove design that minimises the peak blockage is found using a surrogate-based optimisation approach. The implementation of the optimised groove is shown to produce a stall margin improvement of about 5%.

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Schmidt, T., V. Gümmer, and M. Konle. "Potential of surrogate modelling in compressor casing design focussing on rapid tip clearance assessments." Aeronautical Journal 125, no. 1291 (September 2021): 1587–610. http://dx.doi.org/10.1017/aer.2021.39.

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ABSTRACTLosses induced by tip clearance limit decisive improvements in the system efficiency and aerodynamic operational stability of aero-engine axial compressors. The tendency towards even lower blade heights to compensate for higher fluid densities aggravates their influence. Generally, it is emphasised that the tip clearance should be minimised but remain large enough to prevent collisions between the blade tip and the casing throughout the entire mission. The present work concentrates on the development of a preliminary aero-engine axial compressor casing design methodology involving meta-modelling techniques. Previous research work at the Institute for Turbomachinery and Flight Propulsion resulted in a Two-Dimensional (2D) axisymmetric finite element model for a generic multi-stage high-pressure axial compressor casing. Subsequent sensitivity studies led to the identification of significant parameters that are important for fine-tuning the tip clearance via specific flange design. This work is devoted to an exploration of the potential of surrogate modelling in preliminary compressor casing design with respect to rapid tip clearance assessments and its corresponding precision in comparison with finite element results. Reputed as data-driven mathematical approximation models and conceived for inexpensive numerical simulation result reproduction, surrogate models show even greater capacity when linked with extensive design space exploration and optimisation algorithms.Compared with high-fidelity finite element simulations, the reductions obtained in computational time when using surrogate models amount to 99.9%. Validated via statistical methods and dependent on the size of the training database, the precision of surrogate models can reach down to the range of manufacturing tolerances. Subsequent inclusion of such surrogate models in a parametric optimisation process for tip clearance minimisation rapidly returned adaptions of the geometric design variables.

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Kagiri, Charles, Lijun Zhang, and Xiaohua Xia. "A Hierarchical Optimisation of a Compressed Natural Gas Station for Energy and Fuelling Efficiency under a Demand Response Program." Energies 12, no. 11 (June 6, 2019): 2165. http://dx.doi.org/10.3390/en12112165.

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Compressed natural gas stations serve customers who have chosen compressed natural gas powered vehicles as an alternative to diesel and petrol based ones, for cost or environmental reasons. The interaction between the compressed natural gas station and electricity grid requires an energy management strategy to minimise a significant component of the operating costs of the station where demand response programs exist. Such a strategy when enhanced through integration with a control strategy for optimising gas delivery can raise the appeal of the compressed natural gas, which is associated with reduced criteria air pollutants. A hierarchical operation optimisation approach adopted in this study seeks to achieve energy cost reduction for a compressed natural gas station in a time-of-use electricity tariff environment as well as increase the vehicle fuelling efficiency. This is achieved by optimally controlling the gas dispenser and priority panel valve function under an optimised schedule of compressor operation. The results show that electricity cost savings of up to 60.08% are achieved in the upper layer optimisation while meeting vehicle gas demand over the control horizon. Further, a reduction in filling times by an average of 16.92 s is achieved through a lower layer model predictive control of the pressure-ratio-dependent fuelling process.

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Kozakiewicz, Adam, and Rafał Kieszek. "Artificial Neural Network Structure Optimisation in the Pareto Approach on the Example of Stress Prediction in the Disk-Drum Structure of an Axial Compressor." Materials 15, no. 13 (June 24, 2022): 4451. http://dx.doi.org/10.3390/ma15134451.

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The article presents the process of selecting and optimising artificial neural networks based on the example of determining the stress distribution in a disk-drum structure compressor stage of an aircraft turbine engine. The presented algorithm allows the determination of von Mises stress values which can be part of the penalty function for further mass optimization of the structure. A method of a parametric model description of a compressor stage is presented in order to prepare a reduced stress distribution for training artificial neural networks. A comparative analysis of selected neural network training algorithms combined with the optimisation of their structure is presented. A genetic algorithm was used to determine the optimal number of hidden layers and neurons in a layer. The objective function was to minimise the absolute value of the relative error and standard deviation of stresses determined by FEM and artificial neural networks. The results are presented in the form of the Pareto front due to the stochastic optimisation process.

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Aprea, Ciro, and Angelo Maiorino. "On the optimisation of a direct current (dc) hot-wall refrigerator." E3S Web of Conferences 197 (2020): 02007. http://dx.doi.org/10.1051/e3sconf/202019702007.

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This study presents an experimental investigation conducted on a refrigerator powered by direct current and composed of a 166L cabinet, a condenser embedded in the external wall of the compartment (hot-wall), an internal static evaporator, a hermetic variable speed compressor. The refrigerant fluid used is the R290a, a natural fluid. By placing the refrigerator in a temperature-controlled environment, four external temperatures have experimented: 22, 25, 29 and 32 °C. Three different temperature setpoints have been set for each temperature: -5, -10, -20 °C. In this way, 12 test conditions were defined, and each of them was repeated by imposing four different compressor rotation speeds: 2000, 2500, 3000, 3500 rpm. The set of tests allowed to identify for each operating condition the optimal number of operating revolutions aimed at minimising the energy consumption of the analysed device.

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Sultan, Ibrahim A., and Azfar Kalim. "Improving reciprocating compressor performance using a hybrid two‐level optimisation approach." Engineering Computations 28, no. 5 (July 19, 2011): 616–36. http://dx.doi.org/10.1108/02644401111141046.

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Chaczykowski, Maciej. "Organic Rankine Cycle for Residual Heat to Power Conversion in Natural Gas Compressor Station. Part I: Modelling and Optimisation Framework." Archives of Mining Sciences 61, no. 2 (June 1, 2016): 245–58. http://dx.doi.org/10.1515/amsc-2016-0018.

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Abstract Basic organic Rankine cycle (ORC), and two variants of regenerative ORC have been considered for the recovery of exhaust heat from natural gas compressor station. The modelling framework for ORC systems has been presented and the optimisation of the systems was carried out with turbine power output as the variable to be maximized. The determination of ORC system design parameters was accomplished by means of the genetic algorithm. The study was aimed at estimating the thermodynamic potential of different ORC configurations with several working fluids employed. The first part of this paper describes the ORC equipment models which are employed to build a NLP formulation to tackle design problems representative for waste energy recovery on gas turbines driving natural gas pipeline compressors.

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Cvok, Ivan, Igor Ratković, and Joško Deur. "Optimisation of Control Input Allocation Maps for Electric Vehicle Heat Pump-based Cabin Heating Systems." Energies 13, no. 19 (October 2, 2020): 5131. http://dx.doi.org/10.3390/en13195131.

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The heating, ventilation and air conditioning (HVAC) system negatively affects the electric vehicle (EV) driving range, especially under cold ambient conditions. Modern HVAC systems based on the vapour-compression cycle can be rearranged to operate in the heat pump mode to improve the overall system efficiency compared to conventional electrical/resistive heaters. Since such an HVAC system is typically equipped with multiple actuators (compressor, pumps, fans, valves), with the majority of them being controlled in open loop, an optimisation-based control input allocation is necessary to achieve the highest efficiency. This paper presents a genetic algorithm optimisation-based HVAC control input allocation method, which utilises a multi-physical HVAC system model implemented in Dymola/Modelica. The considered control inputs include the cabin inlet air temperature reference, blower and radiator fan air mass flows and secondary coolant loop pumps’ speeds. The optimal allocation is subject to specified, target cabin air temperatures and heating power. Additional constraints include actuator hardware limits and safety functions, such as maintaining the superheat temperature at its reference level. The optimisation objective is to maximise the system efficiency defined by the coefficient of performance (COP). The optimised allocation maps are fitted by proper mathematical functions to facilitate the control strategy implementation and calibration. The overall control strategy consists of superimposed cabin air temperature controller that commands heating power, control input allocation functions, and low-level controllers that ensure cabin inlet air and superheat temperature regulation. The control system performance is verified through Dymola simulations for the heat pump mode in a heat-up scenario. Control input allocation map optimisation results are presented for air-conditioning (A/C) mode, as well.

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Hansen, Laura Debel, Morten Veng, and Petar Durdevic. "Compressor Scheduling and Pressure Control for an Alternating Aeration Activated Sludge Process—A Simulation Study Validated on Plant Data." Water 13, no. 8 (April 9, 2021): 1037. http://dx.doi.org/10.3390/w13081037.

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Aiming at reducing their emissions, wastewater treatment plants (WWTP) seek to reduce their energy consumption, where a large amount is used for the aeration. The case plant, Grindsted WWTP uses an alternating aeration strategy, with a common air supply system facilitating the process in four aeration tanks and thus making optimisation challenging. In this work, a nonlinear model of the air supply system is designed, in which multiple key parameters are estimated by data-driven optimization. Subsequently, a model-based control strategy for scheduling of compressors and desired airflow is proposed, to save energy without compromising the aeration performance. The strategy is based upon partly static- partly dynamic models of the compressors, describing their efficiency in terms of system head and volumetric airflow rate. The simulation study uses real plant data and shows great potential for improvement of energy efficiency, regardless of the aeration pattern in any of the four process tanks, and furthermore contributes to a reduction in compressor restarts per day. The proposed method is applicable to other WWTP with multiple compressors in the air supply system, as this study is conducted using first principle models validated on data from the daily operation.

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Adamson, Richard, Martin Hobbs, Andy Silcock, and Mark J. Willis. "Steady-state optimisation of a multiple cryogenic air separation unit and compressor plant." Applied Energy 189 (March 2017): 221–32. http://dx.doi.org/10.1016/j.apenergy.2016.12.061.

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Zhu, Yujie, Yaping Ju, and Chuhua Zhang. "Proper orthogonal decomposition assisted inverse design optimisation method for the compressor cascade airfoil." Aerospace Science and Technology 105 (October 2020): 105955. http://dx.doi.org/10.1016/j.ast.2020.105955.

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Berger, Ricarda, Benedikt Hofmeister, Cristian G. Gebhardt, and Raimund Rolfes. "A two-objective design optimisation approach for blending repairs of damaged compressor blisks." Aerospace Science and Technology 105 (October 2020): 106022. http://dx.doi.org/10.1016/j.ast.2020.106022.

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Armas, Juan Carlos, Margarita Lapido Rodríguez, Julio Rafael Gómez, and Yarelis Valdivia Nodal. "A thermodynamic evaluation of chilled water central air conditioning systems using artificial intelligence tools." Ingeniería e Investigación 31, no. 2 (May 1, 2011): 134–42. http://dx.doi.org/10.15446/ing.investig.v31n2.23472.

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An analysis of a chilled water central air conditioning system is presented. The object was to calculate main cycle component irreversibility, as well as evaluating this indicator' s sensitivity to operational variations. Artificial neural networks (ANN), genetic algorithms (GA) and Matlab tools were used to calculate refrigerant thermodynamic properties during each cycle stage. These tools interacted with equations describing the system's thermodynamic behaviour. Refrigerant temperature, when released from the compressor, was determined by a hybrid model combining the neural model with a simple genetic algorithm used as optimisation tool; the cycle' s components which were most sensitive to changes in working conditions were identified. It was concluded that the compressor, evaporator and expansion mechanism (in that order) represented significant energy losses reaching 85.62% of total system irreversibility. A very useful tool was thus developed for evaluating these systems.

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Chaczykowski, Maciej. "Organic Rankine Cycle for Residual Heat to Power Conversion in Natural Gas Compressor Station. Part II: Plant Simulation and Optimisation Study." Archives of Mining Sciences 61, no. 2 (June 1, 2016): 259–74. http://dx.doi.org/10.1515/amsc-2016-0019.

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Abstract After having described the models for the organic Rankine cycle (ORC) equipment in the first part of this paper, this second part provides an example that demonstrates the performance of different ORC systems in the energy recovery application in a gas compressor station. The application shows certain specific characteristics, i.e. relatively large scale of the system, high exhaust gas temperature, low ambient temperature operation, and incorporation of an air-cooled condenser, as an effect of the localization in a compressor station plant. Screening of 17 organic fluids, mostly alkanes, was carried out and resulted in a selection of best performing fluids for each cycle configuration, among which benzene, acetone and heptane showed highest energy recovery potential in supercritical cycles, while benzene, toluene and cyclohexane in subcritical cycles. Calculation results indicate that a maximum of 10.4 MW of shaft power can be obtained from the exhaust gases of a 25 MW compressor driver by the use of benzene as a working fluid in the supercritical cycle with heat recuperation. In relation to the particular transmission system analysed in the study, it appears that the regenerative subcritical cycle with toluene as a working fluid presents the best thermodynamic characteristics, however, require some attention insofar as operational conditions are concerned.

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Gibson, Lee, Lee Galloway, Sung in Kim, and Stephen Spence. "Assessment of turbulence model predictions for a centrifugal compressor simulation." Journal of the Global Power and Propulsion Society 1 (July 25, 2017): 2II890. http://dx.doi.org/10.22261/2ii890.

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Abstract Steady-state computational fluid dynamics (CFD) simulations are an essential tool in the design process of centrifugal compressors. Whilst global parameters, such as pressure ratio and efficiency, can be predicted with reasonable accuracy, the accurate prediction of detailed compressor flow fields is a much more significant challenge. Much of the inaccuracy is associated with the incorrect selection of turbulence model. The need for a quick turnaround in simulations during the design optimisation process also demands that the turbulence model selected be robust and numerically stable with short simulation times. In order to assess the accuracy of a number of turbulence model predictions, the current study used an exemplar open test case, the centrifugal compressor “Radiver”, to compare the results of three eddy-viscosity models and two Reynolds stress type models. The turbulence models investigated in this study were: (i) Spalart-Allmaras (SA), (ii) Shear Stress Transport (SST), (iii) a modification to the SST model denoted the SST-curvature correction (SST-CC), (iv) Reynolds stress model of Speziale, Sarkar and Gatski (RSM-SSG), and (v) the turbulence frequency formulated Reynolds stress model (RSM-ω). Each was found to be in good agreement with the experiments (below 2% discrepancy), with respect to total-to-total parameters at three different operating conditions. However, for the near surge operating point P1, local flow field differences were observed between the models, with the SA model showing particularly poor prediction of local flow structures. The SST-CC showed better prediction of curved rotating flows in the impeller. The RSM-ω was better for the wake and separated flow in the diffuser. The SST model showed reasonably stable, robust and time efficient capability to predict global performance and local flow features.

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Zhou, Junqiang, Lisa Fiorentini, and Marcello Canova. "Model-based optimisation and predictive control of a turbocharged diesel engine with variable geometry compressor." International Journal of Powertrains 5, no. 2 (2016): 167. http://dx.doi.org/10.1504/ijpt.2016.076559.

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Jinhuan, Zhang, and Zhou Zhenggui. "An improved genetic algorithm and its applications to the optimisation design of an aspirated compressor profile." International Journal for Numerical Methods in Fluids 79, no. 12 (July 21, 2015): 640–53. http://dx.doi.org/10.1002/fld.4068.

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Du, Yadong, Ce Yang, Haimei Wang, and Chenxing Hu. "One-dimensional optimisation design and off-design operation strategy of centrifugal compressor for supercritical carbon dioxide Brayton cycle." Applied Thermal Engineering 196 (September 2021): 117318. http://dx.doi.org/10.1016/j.applthermaleng.2021.117318.

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Tüchler, Stefan, Zhihang Chen, and Colin D. Copeland. "Multipoint shape optimisation of an automotive radial compressor using a coupled computational fluid dynamics and genetic algorithm approach." Energy 165 (December 2018): 543–61. http://dx.doi.org/10.1016/j.energy.2018.09.076.

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Byrne, Paul, and Pascal Lalanne. "Parametric Study of a Long-Duration Energy Storage Using Pumped-Hydro and Carbon Dioxide Transcritical Cycles." Energies 14, no. 15 (July 21, 2021): 4401. http://dx.doi.org/10.3390/en14154401.

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The urgent energy transition needs a better penetration of renewable energy in the world’s energy mix. The intermittency of renewables requires the use of longer-term storage. The present system uses water displacement, in a lined rock cavern or in an aerial pressurised vessel, as the virtual piston of compressor and expander functions in a carbon dioxide heat pump cycle (HPC) and in an organic transcritical cycle (OTC). Within an impermeable membrane, carbon dioxide is compressed and expanded by filling and emptying pumped-hydro water. Carbon dioxide exchanges heat with two atmospheric thermal storage pits. The hot fluid and ice pits are charged by the HPC when renewable energy becomes available and discharged by the OTC when electricity is needed. A numerical model was built to replicate the system’s losses and to calculate its round-trip efficiency (RTE). A subsequent parametric study highlights key parameters for sizing and optimisation. With an expected RTE of around 70%, this CO2 PHES (pumped-hydro electricity storage) coupled with PTES (pumped thermal energy storage) could become a game-changer by allowing the efficient storage of intermittent renewable energy and by integrating with district heating and cooling networks, as required by cities and industry in the future.

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Cieplok, Grzegorz, and Marian Sikora. "Two-Mass Dynamic Absorber of a Widened Antiresonance Zone." Archive of Mechanical Engineering 62, no. 2 (June 1, 2015): 257–77. http://dx.doi.org/10.1515/meceng-2015-0015.

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Abstract Attempts to perform synthesis of a passive vibroinsulation two-mass system intended for the simultaneous reduction of machine frame vibrations and forces transmitted to foundations by supporting elements were undertaken in the study. In view of the variable frequency of the machine operation, it was necessary for the frequency interval, encompassed by the vibroinsulation system operation, to be within given limits. On the grounds of properties of the linear massive-elastic system formulated in the works of Genkin and Ryaboy (1998), the problem of vibroinsulation system synthesis was formulated in the parametric type optimisation approach with equality and inequality limitations. For piston compressor vibroinsulation, the mass and elasticity matrices of the vibroinsulating system, as well as its physical structure, were determined. Its operation was verified on the basis of simulation investigations, taking into account the system loss and transient states

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Iaria, Davide, Homam Nipkey, Jafar Al Zaili, Abdulnaser Sayma, and Mohsen Assadi. "Development and Validation of a Thermo-Economic Model for Design Optimisation and Off-Design Performance Evaluation of a Pure Solar Microturbine." Energies 11, no. 11 (November 18, 2018): 3199. http://dx.doi.org/10.3390/en11113199.

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The aim of this paper is to present a thermo-economic model of a microturbine for solar dish applications, which demonstrates the applicability and accuracy of the model for off-design performance evaluation and techno-economic optimisation purposes. The model is built using an object-oriented programming approach. Each component is represented using a class made of functions that perform a one-dimensional physical design, off-design performance analysis and the component cost evaluation. Compressor, recuperator, receiver and turbine models are presented and validated against experimental data available in literature, and each demonstrated good accuracy for a wide range of operating conditions. A 7-kWe microturbine and solar irradiation data available for Rome between 2004 and 2005 were considered as a case study, and the thermo-economic analysis of the plant was performed to estimate the levelised cost of electricity based on the annual performance of the plant. The overall energy produced by the plant is 10,682 kWh, the capital cost has been estimated to be EUR 27,051 and, consequently, the specific cost of the plant, defined as the ratio between the cost of components and output power in design condition, has been estimated to be around EUR 3980/kWe. Results from the levelised cost of electricity (LCOE) analysis demonstrate a levelised cost of electricity of EUR 22.81/kWh considering a plant lifetime of 25 years. The results of the present case study have been compared with the results from IPSEpro 7 where the same component characteristic maps and operational strategy were considered. This comparison was aimed to verify the component matching procedure adopted for the present model. A plant sizing optimisation was then performed to determine the plant size which minimises the levelised cost of electricity. The design space of the optimisation variable is limited to the values 0.07–0.16 kg/s. Results of the optimisation demonstrate a minimum LCOE of 21.5 [EUR/kWh] for a design point mass flow rate of about 0.11 kg/s. This corresponds to an overall cost of the plant of around EUR 32,600, with a dish diameter of 9.4 m and an annual electricity production of 13,700 [kWh].

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Al-Sayyab, Ali Khalid Shaker, Joaquín Navarro-Esbrí, Victor Manuel Soto-Francés, and Adrián Mota-Babiloni. "Conventional and Advanced Exergoeconomic Analysis of a Compound Ejector-Heat Pump for Simultaneous Cooling and Heating." Energies 14, no. 12 (June 13, 2021): 3511. http://dx.doi.org/10.3390/en14123511.

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This work focused on a compound PV/T waste heat driven ejector-heat pump system for simultaneous data centre cooling and waste heat recovery for district heating. The system uses PV/T waste heat as the generator’s heat source, acting with the vapour generated in an evaporative condenser as the ejector drive force. Conventional and advanced exergy and advanced exergoeconomic analyses are used to determine the cause and avoidable degree of the components’ exergy destruction rate and cost rates. Regarding the conventional exergy analysis for the whole system, the compressor represents the largest exergy destruction source of 26%. On the other hand, the generator shows the lowest sources (2%). The advanced exergy analysis indicates that 59.4% of the whole system thermodynamical inefficiencies can be avoided by further design optimisation. The compressor has the highest contribution to the destruction in the avoidable exergy destruction rate (21%), followed by the ejector (18%) and condenser (8%). Moreover, the advanced exergoeconomic results prove that 51% of the system costs are unavoidable. In system components cost comparison, the highest cost comes from the condenser, 30%. In the same context, the ejector has the lowest exergoeconomic factor, and it should be getting more attention to reduce the irreversibility by design improving. On the contrary, the evaporator has the highest exergoeconomic factor (94%).

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Chernova, Oksana, Oleg Vytyaz, Rostislav Martyniuk, and Irina Fedorovych. "Rational methods of operation of underground gas storages and mitigation of energy losses." Nafta-Gaz 78, no. 3 (March 2022): 187–96. http://dx.doi.org/10.18668/ng.2022.03.03.

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The fuel and energy complex of Ukraine, like most developed countries of the world, is a complex system of material production incorporating a set of many subsystems that cover the extraction, conversion, distribution, storage and consumption of energy. Ukraine's gas transportation system has an extremely complex system, which consists of gas pipelines of various purposes and capacities, compressor stations, compressor shops, gas distribution stations and underground gas storage facilities. Compressor stations, allied with underground storage, ensure full pipeline use, reliability of work, modes of regulation of transit flows and maintenance of uninterrupted supply. Their co-employment is considered one of the most effective methods of increasing reserves for reliable gas supply and efficiency of gas sales in the country and abroad. The use of storage reduces the unevenness of seasonal consumption and enables timely delivery. This is justified by the fact that during the year, gas production is uneven, as is consumption. In winter, the amount of gas extracted does not provide the amount of gas consumed. Therefore, underground storage facilities are an integral part of the gas transmission system, which must function efficiently. The Ukrainian gas transportation system is part of the European energy system, despite the fact that the country itself is not yet a member of the EU. To research the issues of improving the efficiency of the system and underground storage facilities, it is necessary to analyse the parameters of their work and study the problems of reducing costs during storage and transportation. In the work on the basis of the analysis of the cyclic operation of the Dashavsky underground storage, the energy approach to an estimation of losses of gas at storage is offered. This will streamline and specify the general ideas and the level of irreversible losses of natural gas as an energy source and will increase the efficiency of operation of the underground gas storage as a whole. At the same time, taking into account the energy characteristics of natural gas when forecasting its losses during storage will significantly affect the organisation and optimisation of maintenance of storage equipment and, in particular, the compressor station.

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Pearson, Robert, Shona Mackenzie, Lyle Burke, and Keith Reimer. "Planning and optimisation of large, complex, low pressure gas and water gathering systems." APPEA Journal 50, no. 2 (2010): 683. http://dx.doi.org/10.1071/aj09047.

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Modelling low pressure gas gathering systems for unconventional gas (UCG) and coal seam gas (CSG) or coal bed methane (CBM) developments is challenged by: the sensitivity of well performance to system back-pressure; statistical uncertainties over well performance and areal variability in pay quality; the rapid build-up of friction with gas velocity; the rate of conversion from planning assumptions to real data on wells and lines; commissioning and initial well test reliability issues; modelling transient well performance using steady state solutions; unpredictable peak rates and rapid initial declines from those peak rates; well interference effects; large development areas with multiple gathering stations; line looping and bi-directional lines required to accommodate compressor outages; and, new gas treatment and transmission facilities being added onto existing system during development drilling operations. Moreover, many of these systems have multiple gas delivery points at different delivery pressures. Similarly, low pressure water gathering, storage, processing and delivery systems involve features that are not common in conventional water injection or salt water disposal networks, such as: large numbers of wells tied-in using lines with very low pressure ratings; water storage ponds or tanks that may involve evaporation losses; gravity feed or back-flow during intermittent pumping; infield modifications to accommodate overload situations that had not gone through a formal design change process; and, intermittent transfer operations to take advantage of reduced power costs during the night, or to avoid peak demand penalties. This paper will look at two case histories from North America that had to address many of these problems. The objective is to capture lessons learned to assist in the challenges that we are currently facing in ramping-up CSG production in eastern Australia.

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Pérez Arroyo, Carlos, Jérôme Dombard, Florent Duchaine, Laurent Gicquel, Benjamin Martin, Nicolas Odier, and Gabriel Staffelbach. "Towards the Large-Eddy Simulation of a full engine: Integration of a 360 azimuthal degrees fan, compressor and combustion chamber. Part I: Methodology and initialisation." Journal of the Global Power and Propulsion Society, May (May 25, 2021): 1–16. http://dx.doi.org/10.33737/jgpps/133115.

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Optimising the design of aviation propulsion systems using computational fluid dynamics is essential to increase their efficiency and reduce pollutant as well as noise emissions. Nowadays, and within this optimisation and design phase, it is possible to perform meaningful unsteady computations of the various components of a gas-turbine engine. However, these simulations are often carried out independently of each other and only share averaged quantities at the interfaces minimising the impact and interactions between components. In contrast to the current state-of-the-art, this work presents a 360 azimuthal degrees large-eddy simulation with over 2100 million cells of the DGEN-380 demonstrator engine enclosing a fully integrated fan, compressor and annular combustion chamber at take-off conditions as a first step towards a high-fidelity simulation of the full engine. In order to carry such a challenging simulation and reduce the computational cost, the initial solution is interpolated from stand-alone sectoral simulations of each component. In terms of approach, the integrated mesh is generated in several steps to solve potential machine dependent memory limitations. It is then observed that the 360 degrees computation converges to an operating point with less than 0.5% difference in zero-dimensional values compared to the stand-alone simulations yielding an overall performance within 1% of the designed thermodynamic cycle. With the presented methodology, convergence and azimuthally decorrelated results are achieved for the integrated simulation after only 6 fan revolutions.

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Tkachenko, A. Yu, V. N. Rybakov, E. P. Filinov, and Ya A. Ostapyuk. "Thermodynamic Design of a Small-Scale Gas Turbine Engine Family." Herald of the Bauman Moscow State Technical University. Series Mechanical Engineering, no. 3 (126) (June 2019): 41–53. http://dx.doi.org/10.18698/0236-3941-2019-3-41-53.

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The paper presents a procedure for selecting work cycle parameters and describes thermodynamic design of a small-scale gas turbine engine family consisting of a small-scale gas turbine engine and a gas turbine plant comprising a free turbine driving a power generator, on the basis of a standardized gas generator. In order to select reasonable work cycle parameter values for the small-scale gas turbine engine and gas turbine plant we used a non-linear optimisation technique accounting for functional and parametric constraints as implemented in the ASTRA CAE software. Calculation results allowed us to plot the locally optimal work cycle parameter regions for the small-scale gas turbine engine and gas turbine plant according to the efficiency criteria for both engines, which are specific fuel consumption and net energy conversion efficiency. Taking the constraints into account, we selected reasonable values for the standardized gas generator parameters within the compromise region obtained, specifically the turbine inlet temperature and compressor pressure ratio. Our quantitative results show how the efficiency indices decline in the engine family featuring a standardized gas generator as compared to engines equipped with individually tailored gas generators. Designing a standardized gas generator in advance makes it possible to decrease engine development costs and time, ensure a higher reliability and a lower cost of production.

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Georgiou, Charalampos, and Ulugbek Azimov. "Analysis and Multi-Parametric Optimisation of the Performance and Exhaust Gas Emissions of a Heavy-Duty Diesel Engine Operating on Miller Cycle." Energies 13, no. 14 (July 20, 2020): 3724. http://dx.doi.org/10.3390/en13143724.

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A major issue nowadays that concerns the pollution of the environment is the emissions emerging from heavy-duty internal combustion engines. Such concern is dictated by the fact that the electrification of heavy-duty transport still remains quite challenging due to limitations associated with mileage, charging speed and payload. Further improvements in the performance and emission characteristics of conventional heavy-duty diesel engines are required. One of a few feasible approaches to simultaneously improve the performance and emission characteristics of a diesel engine is to convert it to operate on Miller cycle. Therefore, this study was divided into two stages, the first stage was the simulation of a heavy-duty turbocharged diesel engine (4-stroke, 6-cylinder and 390 kW) to generate data that will represent the reference model. The second stage was the application of Miller cycle to the conventional diesel engine by changing the degrees of intake valve closure and compressor pressure ratio. Both stages have been implemented through the specialist software which was able to simulate and represent a diesel engine based on performance and emissions data. An objective of this extensive investigation was to develop several models in order to compare their emissions and performances and design a Miller cycle engine with an ultimate goal to optimize diesel engine for improved performance and reduced emissions. This study demonstrates that Miller cycle diesel engines could overtake conventional diesel engines for the reduced exhaust gas emissions at the same or even better level of performance. This study shows that, due to the dependence of engine performance on complex multi-parametric operation, only one model achieved the objectives of the study, more specifically, engine power and torque were increased by 5.5%, whilst nitrogen oxides and particulate matter were decreased by 30.2% and 5.5%, respectively, with negligible change in specific fuel consumption and CO2, as average values over the whole range of engine operating regimes.

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Maddumala, Dr Ramakotaiah. "Structural Analysis of Gas Turbine Blade." International Journal for Research in Applied Science and Engineering Technology 9, no. VI (June 20, 2021): 1338–52. http://dx.doi.org/10.22214/ijraset.2021.35267.

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A turbine blade is a machine component which makes up the turbine section of a gas turbine. These blades are responsible for extracting energy from the high temperature, high pressure gas produced by the combustor. The turbine blades are often the limiting component of the gas turbine. To survive in this difficult environment , turbine blades often use exotic materials like super alloys and many different methods of cooling , such as internal air channels and thermal barrier coatings. A common failure mode for turbine machine is high cycle of fatigue of compressor and turbine blades due to high dynamic stress caused by blade vibration and temperature has significant effect on gas turbine blades. The stresses with detrimental effect to the nozzle and blade were principally of thermal type, developed due to high temperature gradients across the air foil wall. These generate thermal fatigue mechanism and high steady state load leading to creep mechanism. In this project, a turbine blade is designed and modelled in NX Unigraphics software which is an advanced high-end CAD/CAE/CAM. The design is modified by changing the base of the blade to increase overall efficiency. Since the design of turbo machinery is complex and efficiency is directly related to material performance and material selection is of prime importance. In this project few materials are considered for turbine blade –titanium alloy and Nickel alloy. Optimisation will be done by varying the materials by performing structural analysis and thermal analysis on the turbine blades for both the designs

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Stosic, N., I. K. Smith, and A. Kovacevic. "Optimisation of screw compressors." Applied Thermal Engineering 23, no. 10 (July 2003): 1177–95. http://dx.doi.org/10.1016/s1359-4311(03)00059-0.

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Cheayb, Mohamad, Sébastien Poncet, Mylène Marin-Gallego, and Mohand Tazerout. "Parametric Optimisation of a Trigenerative Small Scale Compressed Air Energy Storage System." Proceedings 23, no. 1 (August 23, 2019): 5. http://dx.doi.org/10.3390/proceedings2019023005.

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Recently, major improvement on compressed air energy storage technology has been made by using the heat of compression for heating energy or using it to preheat the compressed air in the expansion phase and by demonstrating its ability to produce cooling energy. Thus, the trigenerative compressed air energy storage has been introduced. In this paper, we introduce a configuration of trigenerative compressed air energy storage system giving the preference to the electric energy production. The study then focuses on undertaking an optimization study via a parametric analysis considering the mutual effects of parameters. This analysis is applied to a micro-scale application including the existing technological aspects. The parametric study results applied on the hot temperature of the thermal energy storage indicate the possibility to find an optimal solution as a trade-off between system performances and other parameters reflecting its cost. On the contrary, the selection of the maximal storage pressure cannot be achieved by finding a compromise between energy density and system efficiency. A complete study of other design parameters will be addressed in a future publication.

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Li-Mayer, J. Y. S., M. Martinez, J. Lambros, and M. N. Charalambides. "Determination of Mixed-Mode Cohesive Zone Failure Parameters Using Digital Volume Correlation and the Inverse Finite Element Method." Key Engineering Materials 774 (August 2018): 72–76. http://dx.doi.org/10.4028/www.scientific.net/kem.774.72.

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The suitability of an optimisation workflow for the determination of the mixed-mode cohesive zone model parameters using digital volume correlation (DVC) data and the inverse finite element method was examined. A virtual compression experiment of a cylinder with a spherical inclusion was modelled using the finite element method. A bilinear traction separation law with a linear mixed-mode relationship was used to describe the interfacial behaviour. Known mode I and mode II fracture energies, = 20 J/m2 and = 40 J/m2 and damage initiation stress, = 0.09 MPa, were used to generate a target composite debonding behaviour. An objective function,, determined based on the debonding behaviour measurable by DVC was chosen. A full factorial experiment was carried out for the four cohesive parameters and showed that correlation between fracture energies/ damage initiation stresses and is non-linear and discontinuous with multiple local minima. Optimisations initiated at the local minima identified from the full factorial experiment correctly determined the target cohesive fracture energies and damage initiation stresses.

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Khandelwal, A., and K. S. Rajan. "QUERY SUPPORT FOR GMZ." ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences XLII-4/W2 (July 5, 2017): 95–99. http://dx.doi.org/10.5194/isprs-archives-xlii-4-w2-95-2017.

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Generic text-based compression models are simple and fast but there are two issues that needs to be addressed. They cannot leverage the structure that exists in data to achieve better compression and there is an unnecessary decompression step before the user can actually use the data. To address these issues, we came up with GMZ, a lossless compression model aimed at achieving high compression ratios. The decision to design GMZ (Khandelwal and Rajan, 2017) exclusively for GML's Simple Features Profile (SFP) seems fair because of the high use of SFP in WFS and that it facilitates high optimisation of the compression model. This is an extension of our work on GMZ. In a typical server-client model such as Web Feature Service, the server is the primary creator and provider of GML, and therefore, requires compression and query capabilities. On the other hand, the client is the primary consumer of GML, and therefore, requires decompression and visualisation capabilities. In the first part of our work, we demonstrated compression using a python script that can be plugged in a server architecture, and decompression and visualisation in a web browser using a Firefox addon. The focus of this work is to develop the already existing tools to provide query capability to server. Our model provides the ability to decompress individual features in isolation, which is an essential requirement for realising query in compressed state. We con - struct an R-Tree index for spatial data and a custom index for non-spatial data and store these in a separate index file to prevent alter - ing the compression model. This facilitates independent use of compressed GMZ file where index can be constructed when required. The focus of this work is the bounding-box or range query commonly used in webGIS with provision for other spatial and non-spatial queries. The decrement in compression ratios due to the new index file is in the range of 1&ndash;3 percent which is trivial considering the benefits of querying in compressed state. With around 75&thinsp;% average compression of the original data, query support in compressed state and decompression support in the browser, GMZ can be a good alternative to GML for WFS-like services.

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JV, Anand. "Trust-Value Based Wireless Sensor Network Using Compressed Sensing." June 2020 2, no. 2 (June 2, 2020): 88–95. http://dx.doi.org/10.36548/jei.2020.2.003.

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Wireless sensor networks have quickly paved way to novel ways of communication between two nodes. They consist of sensor nodes that have the capacity to sense, communicate and compute. If a particular node in a WSN is not able to transmit data to the base station, routing algorithms will move into action to direct the data from the node. The proposed work deals with a routing algorithm based on trust awareness and compression sensing data, to handle data routing in a clustered WSN. In general, when sensor nodes have reduced overhead, compressed sensing is utilized for data aggregation. In order to strike a balance between number of messages transmitted, hop count, distance of transmission and the optimal trusted path, many nature inspired optimisation methods have been developed over the years. However, trust-based retrieval of compressed data is executed at the base station amidst malicious nodes.

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Amirjanov, Adil, and Kamil Dimililer. "Image compression system with an optimisation of compression ratio." IET Image Processing 13, no. 11 (September 19, 2019): 1960–69. http://dx.doi.org/10.1049/iet-ipr.2019.0114.

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Haugland, D., J. G. Heber, and J. H. Husøy. "Optimisation algorithms for ECG data compression." Medical & Biological Engineering & Computing 35, no. 4 (July 1997): 420–24. http://dx.doi.org/10.1007/bf02534101.

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Bontempo, R., and M. Manna. "Efficiency optimisation of advanced gas turbine recuperative-cycles." Proceedings of the Institution of Mechanical Engineers, Part A: Journal of Power and Energy 234, no. 6 (October 1, 2019): 817–35. http://dx.doi.org/10.1177/0957650919875909.

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The paper presents a theoretical analysis of three advanced gas turbine recuperative-cycles, that is, the intercooled, the reheat and the intercooled and reheat cycles. The internal irreversibilities, which characterise the compression and expansion processes, are taken into account through the polytropic efficiencies of the compressors and turbines. As customary in simplified analytical approaches, the study is carried out for an uncooled closed-circuit gas turbine without pressure losses in the heat exchangers and using a calorically perfect gas as working fluid. Although the accurate performance prediction of a real-gas turbine is prevented by these simplifying assumptions, this analysis provides a fast and simple approach which can be used to theoretically explain the main features of the three advanced cycles and to compare them highlighting pros and contra. The effect of the heat recuperation is investigated comparing the thermal efficiency of a given cycle type with those of two reference cycles, namely, the non-recuperative version of the analysed cycle and the simple cycle. As a result, the ranges of the intermediate pressure ratios returning a benefit in the thermal efficiency in comparison with the two reference cycles have been obtained for the first time. Finally, for the sole intercooled and reheat recuperative-cycle, a novel analytical expression for the intermediate pressure ratios yielding the maximum thermal efficiency is also given.

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Song, Jie, Xiaodong Peng, Xiangjun Fang, Ying Han, Zhanfeng Deng, Guizhi Xu, Lixiao Liang, Jibiao Hou, and Hongwei Wu. "Thermodynamic analysis and algorithm optimisation of a multi-stage compression adiabatic compressed air energy storage system." Thermal Science and Engineering Progress 19 (October 2020): 100598. http://dx.doi.org/10.1016/j.tsep.2020.100598.

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Journal articles on the topic 'Compressor optimisation'

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