The Experts below are selected from a list of 2952 Experts worldwide ranked by ideXlab platform
Eckhard A. Groll - One of the best experts on this subject based on the ideXlab platform.
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Optimization of a Scroll Compressor for liquid flooding
International Journal of Refrigeration, 2012Co-Authors: Ian H. Bell, Eckhard A. Groll, James E. Braun, Galen B. King, W. Travis HortonAbstract:In two companion papers, simulation models for the working processes of liquid-flooded Scroll Compressors and expanders have been developed and validated against experimental data. In this study, analytic models are presented for the modes of irreversibility generation in the liquid-flooded Scroll Compressor including built-in volume ratio maladjustment, pressure drop and leakage. A thermodynamic model is used to derive the ideal volume ratio for a liquid-flooded Compressor, which is higher than that of dry compression. An optimum set of built-in volume ratio and Scroll base circle radius is found which maximizes the overall isentropic efficiency by minimizing the leakage and pressure drop irreversibilities. The irreversibility generation models are used to optimize a Scroll Compressor for the Liquid-Flooded Ericsson cycle application. The model predicts Scroll Compressor overall isentropic efficiency of over 80% (based on the shaft power) at an oil mass fraction of 88%.
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Update on Scroll Compressor Chamber Geometry
2010Co-Authors: Ian H. Bell, Eckhard A. Groll, James E. Braun, Galen B. KingAbstract:The geometry of the Scroll Compressor determines the efficiency of the Scroll Compressor and controls all elements of its operation. It is therefore critical to be able to accurately model the volumes of the Compressor over the course of a revolution. This paper proposes a novel quasianalytic formulation of the suction, compression a chambers based on a change of variables from involute angle to polar integration angle. This solution has been compared against a reference polygon solution, and for the suction chamber this solution agrees to within 0.02%. The solutions for the compression and discharge chamber volumes are analytic and incur a negligible penalty to overhead of a detailed Compressor model. In addition, the general nature of the solution presented allows for multiple compression chambers and more complex discharge geometry.
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Analysis of liquid-flooded compression using a Scroll Compressor.
2008Co-Authors: Ian H. Bell, Vincent Lemort, James E. Braun, Eckhard A. GrollAbstract:ABSTRACT One possible means of decreasing the work of compression of a Scroll gas Compressor is by injecting, or flooding, high specific heat liquid into the inlet gas stream of the Compressor. The high specific heat liquid can then absorb the heat of compression of the gas and offer the possibility of a reduction in the net power of the Compressor. The particular application of interest for this flooded-compression technology is the Liquid-Flooded Ericsson cycle as proposed by Hugenroth et al. (2007), a gas refrigeration cycle. Adequate performance of the Ericsson cycle is contingent on designing Scroll Compressors that can efficiently compress high heat of compression gases. A detailed model of the flooded Scroll Compressor has been constructed which allows prediction of the Compressor performance over a wide range of operating conditions. The detailed flooded Scroll Compressor model has been validated with experimental data, for which good agreement was found. 1. INTRODUCTION A vapor-compression Scroll Compressor has been modified to run on a mixture of gas and oil. Originally the Compressor was an automotive R134a Compressor, but due to its semi-hermetic design it could easily be modified for use with liquid flooding. The radial compliance and discharge valve were removed, but otherwise the Compressor was off-the-shelf. Previous investigators (Li 1992, Hiwata 2002, Oku 2006) have experimentally researched flooded compression in Scroll Compressors, though their studies were based on vapor compression systems, and the Compressors were not optimized for liquid flooding.
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mathematical modeling of Scroll Compressors part ii overall Scroll Compressor modeling
International Journal of Refrigeration-revue Internationale Du Froid, 2002Co-Authors: Yu Chen, James E. Braun, Nils P. Halm, Eckhard A. GrollAbstract:Abstract This paper presents the development of a comprehensive simulation model of a horizontal Scroll Compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of Scroll Compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall Compressor model. In the overall model, Compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different Compressor chambers, the temperature distributions in the Scroll wraps, and the temperatures of the other Compressor elements can be obtained. Thereafter, power consumption and efficiency of the Compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall Compressor model, a parametric study of the Scroll Compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive Scroll Compressor model is capable of predicting real Compressor behavior and useful to the design and optimization of Scroll Compressors.
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Mathematical modeling of Scroll Compressors — part II: overall Scroll Compressor modeling
International Journal of Refrigeration, 2002Co-Authors: Yu Chen, James E. Braun, Nils P. Halm, Eckhard A. GrollAbstract:Abstract This paper presents the development of a comprehensive simulation model of a horizontal Scroll Compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of Scroll Compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall Compressor model. In the overall model, Compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different Compressor chambers, the temperature distributions in the Scroll wraps, and the temperatures of the other Compressor elements can be obtained. Thereafter, power consumption and efficiency of the Compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall Compressor model, a parametric study of the Scroll Compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive Scroll Compressor model is capable of predicting real Compressor behavior and useful to the design and optimization of Scroll Compressors.
Baolong Wang - One of the best experts on this subject based on the ideXlab platform.
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optimization of refrigeration system with gas injected Scroll Compressor
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Baolong Wang, Xianting LiAbstract:Gas refrigerant injection has been proven as an effective method to improve the performance of the Scroll Compressor and its refrigeration system under high compression ratio working conditions. Much research on the injected Scroll Compressor and its system has been conducted, but the universal control and design method is still lacking. A model of the refrigeration system with a gas-injected Scroll Compressor is developed in this paper. With this model, the effects of gas injection on the system and component parameters are investigated. Based on the identified evaporator characteristics and thermodynamic analysis, a set of general principles for the design and operation of the refrigeration or heat pump system with a gas-injected Scroll Compressor is proposed.
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Numerical analysis on the effects of refrigerant injection on the Scroll Compressor
Applied Thermal Engineering, 2009Co-Authors: Baolong Wang, Wenxing ShiAbstract:Refrigerant injection is an effective method to improve the performance of the Scroll Compressor and its system under high compression ratio working conditions. This paper intends to find the exhaustive relationship between the injection parameters and the Compressor’s performance. Based on a thermodynamic model, the effects of various parameters of refrigerant injection on general performance and inner compression process of Scroll Compressor have been investigated. As a result, it is found that the injected Scroll Compressor will get the maximum indicated efficiency when the ratio of inner compression ratio and outer compression ratio is a right value. The right value is 1 for the isentropic compression process, and smaller than 1 for a real compression process. Finally, the effects of all the injection factors on the compression work, refrigerant mass flow rate, p–h diagram, volumetric efficiency, and indicated efficiency are investigated detailedly.
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Numerical research on the Scroll Compressor with refrigeration injection
Applied Thermal Engineering, 2007Co-Authors: Baolong Wang, Wenxing Shi, Qisen YanAbstract:Abstract A general model for a Scroll Compressor with refrigerant injection is established in this paper. The model can be used to predict the macro performance and inner compression process of the injected Scroll Compressor. A series of experiments are conducted to validate the accuracy of the model. The results show that the model can precisely predict not only the general performance of the Compressor but also the inner compression with or without refrigerant injection. Based on the thermodynamic model and the test bench, the injection process of the Scroll Compressor has been investigated and the thermodynamic essence is revealed. It is found that the refrigerant injection process can be considered as a continual parameter-varying “adiabatic throttling + isobaric mixture” time-varying process.
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design of experimental bench and internal pressure measurement of Scroll Compressor with refrigerant injection
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: Baolong Wang, Xianting LiAbstract:Experiments on the inner compression process of Scroll Compressor with refrigerant injection can reveal the essence of refrigerant injection. The difficulty of the experiment is the design of location of measuring ports, measuring system of dynamic pressure and design of the injection system. Focusing on the dynamic pressure measurement of inner compression process during refrigerant injection, an integrated bench design method for refrigerant injection research in Scroll Compressor is presented in this paper. The location design of injection ports and measuring ports, frequency spectrum analysis of pressure signal, selection of the sensor type and configuration, and design of the pressure-leading system are expressed, respectively. Finally, a test bench is set up. Based on it, several elementary experiments were carried out. The results show that: this design method solves most problems in the experimental research of Scroll Compressor with refrigerant injection and works reliably; the refrigerant injection effects the majority of the inner compression process and should not be considered as a transient process; gas injection can increase the system performance greatly and there is an optimal injection pressure for a certain Scroll Compressor.
Xianting Li - One of the best experts on this subject based on the ideXlab platform.
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optimization of refrigeration system with gas injected Scroll Compressor
International Journal of Refrigeration-revue Internationale Du Froid, 2009Co-Authors: Baolong Wang, Xianting LiAbstract:Gas refrigerant injection has been proven as an effective method to improve the performance of the Scroll Compressor and its refrigeration system under high compression ratio working conditions. Much research on the injected Scroll Compressor and its system has been conducted, but the universal control and design method is still lacking. A model of the refrigeration system with a gas-injected Scroll Compressor is developed in this paper. With this model, the effects of gas injection on the system and component parameters are investigated. Based on the identified evaporator characteristics and thermodynamic analysis, a set of general principles for the design and operation of the refrigeration or heat pump system with a gas-injected Scroll Compressor is proposed.
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design of experimental bench and internal pressure measurement of Scroll Compressor with refrigerant injection
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: Baolong Wang, Xianting LiAbstract:Experiments on the inner compression process of Scroll Compressor with refrigerant injection can reveal the essence of refrigerant injection. The difficulty of the experiment is the design of location of measuring ports, measuring system of dynamic pressure and design of the injection system. Focusing on the dynamic pressure measurement of inner compression process during refrigerant injection, an integrated bench design method for refrigerant injection research in Scroll Compressor is presented in this paper. The location design of injection ports and measuring ports, frequency spectrum analysis of pressure signal, selection of the sensor type and configuration, and design of the pressure-leading system are expressed, respectively. Finally, a test bench is set up. Based on it, several elementary experiments were carried out. The results show that: this design method solves most problems in the experimental research of Scroll Compressor with refrigerant injection and works reliably; the refrigerant injection effects the majority of the inner compression process and should not be considered as a transient process; gas injection can increase the system performance greatly and there is an optimal injection pressure for a certain Scroll Compressor.
James E. Braun - One of the best experts on this subject based on the ideXlab platform.
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Optimization of a Scroll Compressor for liquid flooding
International Journal of Refrigeration, 2012Co-Authors: Ian H. Bell, Eckhard A. Groll, James E. Braun, Galen B. King, W. Travis HortonAbstract:In two companion papers, simulation models for the working processes of liquid-flooded Scroll Compressors and expanders have been developed and validated against experimental data. In this study, analytic models are presented for the modes of irreversibility generation in the liquid-flooded Scroll Compressor including built-in volume ratio maladjustment, pressure drop and leakage. A thermodynamic model is used to derive the ideal volume ratio for a liquid-flooded Compressor, which is higher than that of dry compression. An optimum set of built-in volume ratio and Scroll base circle radius is found which maximizes the overall isentropic efficiency by minimizing the leakage and pressure drop irreversibilities. The irreversibility generation models are used to optimize a Scroll Compressor for the Liquid-Flooded Ericsson cycle application. The model predicts Scroll Compressor overall isentropic efficiency of over 80% (based on the shaft power) at an oil mass fraction of 88%.
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Update on Scroll Compressor Chamber Geometry
2010Co-Authors: Ian H. Bell, Eckhard A. Groll, James E. Braun, Galen B. KingAbstract:The geometry of the Scroll Compressor determines the efficiency of the Scroll Compressor and controls all elements of its operation. It is therefore critical to be able to accurately model the volumes of the Compressor over the course of a revolution. This paper proposes a novel quasianalytic formulation of the suction, compression a chambers based on a change of variables from involute angle to polar integration angle. This solution has been compared against a reference polygon solution, and for the suction chamber this solution agrees to within 0.02%. The solutions for the compression and discharge chamber volumes are analytic and incur a negligible penalty to overhead of a detailed Compressor model. In addition, the general nature of the solution presented allows for multiple compression chambers and more complex discharge geometry.
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Analysis of liquid-flooded compression using a Scroll Compressor.
2008Co-Authors: Ian H. Bell, Vincent Lemort, James E. Braun, Eckhard A. GrollAbstract:ABSTRACT One possible means of decreasing the work of compression of a Scroll gas Compressor is by injecting, or flooding, high specific heat liquid into the inlet gas stream of the Compressor. The high specific heat liquid can then absorb the heat of compression of the gas and offer the possibility of a reduction in the net power of the Compressor. The particular application of interest for this flooded-compression technology is the Liquid-Flooded Ericsson cycle as proposed by Hugenroth et al. (2007), a gas refrigeration cycle. Adequate performance of the Ericsson cycle is contingent on designing Scroll Compressors that can efficiently compress high heat of compression gases. A detailed model of the flooded Scroll Compressor has been constructed which allows prediction of the Compressor performance over a wide range of operating conditions. The detailed flooded Scroll Compressor model has been validated with experimental data, for which good agreement was found. 1. INTRODUCTION A vapor-compression Scroll Compressor has been modified to run on a mixture of gas and oil. Originally the Compressor was an automotive R134a Compressor, but due to its semi-hermetic design it could easily be modified for use with liquid flooding. The radial compliance and discharge valve were removed, but otherwise the Compressor was off-the-shelf. Previous investigators (Li 1992, Hiwata 2002, Oku 2006) have experimentally researched flooded compression in Scroll Compressors, though their studies were based on vapor compression systems, and the Compressors were not optimized for liquid flooding.
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mathematical modeling of Scroll Compressors part ii overall Scroll Compressor modeling
International Journal of Refrigeration-revue Internationale Du Froid, 2002Co-Authors: Yu Chen, James E. Braun, Nils P. Halm, Eckhard A. GrollAbstract:Abstract This paper presents the development of a comprehensive simulation model of a horizontal Scroll Compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of Scroll Compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall Compressor model. In the overall model, Compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different Compressor chambers, the temperature distributions in the Scroll wraps, and the temperatures of the other Compressor elements can be obtained. Thereafter, power consumption and efficiency of the Compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall Compressor model, a parametric study of the Scroll Compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive Scroll Compressor model is capable of predicting real Compressor behavior and useful to the design and optimization of Scroll Compressors.
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Mathematical modeling of Scroll Compressors — part II: overall Scroll Compressor modeling
International Journal of Refrigeration, 2002Co-Authors: Yu Chen, James E. Braun, Nils P. Halm, Eckhard A. GrollAbstract:Abstract This paper presents the development of a comprehensive simulation model of a horizontal Scroll Compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of Scroll Compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall Compressor model. In the overall model, Compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different Compressor chambers, the temperature distributions in the Scroll wraps, and the temperatures of the other Compressor elements can be obtained. Thereafter, power consumption and efficiency of the Compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall Compressor model, a parametric study of the Scroll Compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive Scroll Compressor model is capable of predicting real Compressor behavior and useful to the design and optimization of Scroll Compressors.
Yu Chen - One of the best experts on this subject based on the ideXlab platform.
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mathematical modeling of Scroll Compressors part ii overall Scroll Compressor modeling
International Journal of Refrigeration-revue Internationale Du Froid, 2002Co-Authors: Yu Chen, James E. Braun, Nils P. Halm, Eckhard A. GrollAbstract:Abstract This paper presents the development of a comprehensive simulation model of a horizontal Scroll Compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of Scroll Compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall Compressor model. In the overall model, Compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different Compressor chambers, the temperature distributions in the Scroll wraps, and the temperatures of the other Compressor elements can be obtained. Thereafter, power consumption and efficiency of the Compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall Compressor model, a parametric study of the Scroll Compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive Scroll Compressor model is capable of predicting real Compressor behavior and useful to the design and optimization of Scroll Compressors.
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Mathematical modeling of Scroll Compressors — part II: overall Scroll Compressor modeling
International Journal of Refrigeration, 2002Co-Authors: Yu Chen, James E. Braun, Nils P. Halm, Eckhard A. GrollAbstract:Abstract This paper presents the development of a comprehensive simulation model of a horizontal Scroll Compressor, which combines a detailed compression process model (Chen Y., Halm N., Groll E., Braun J. Mathematical modelling of Scroll Compressors — part I: compression process modeling, International Journal of Refrigeration 2002;25(6):731–750) and an overall Compressor model. In the overall model, Compressor components are analyzed in terms of nine different elements. Steady state energy balance equations are established applying the lumped capacitance method. In combination with the detailed compression process model, these equations were implemented into computer code and solved recursively. In this way, the temperature and pressure of the refrigerant in different Compressor chambers, the temperature distributions in the Scroll wraps, and the temperatures of the other Compressor elements can be obtained. Thereafter, power consumption and efficiency of the Compressor can be calculated. Tests were used to verify the overall model on a macroscopic basis. Using the simulation program based on the overall Compressor model, a parametric study of the Scroll Compressor was performed, and the effects of internal leakage and heat transfer losses were investigated and some preliminary results were obtained. These results indicate that the comprehensive Scroll Compressor model is capable of predicting real Compressor behavior and useful to the design and optimization of Scroll Compressors.
