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Xianting Li - One of the best experts on this subject based on the ideXlab platform.

  • Experimental investigation on the characteristics of variable displacement swash plate compressor
    Applied Thermal Engineering, 2009
    Co-Authors: Changqing Tian, Li Qin Zhang, Hongbo Xu, Xianting Li
    Abstract:

    Abstract This paper is on a new device developed to measure the Piston Stroke length (PSL) of the variable displacement swash plate compressor (VDSC), with which the test bench for the VDSC and test system for automotive air conditioner with VDSC is constructed. The volumetric efficiency, PSL and displacement control, and transient behavior along with air conditioning load or compressor rotary speed are investigated experimentally. The experiment results show that the volumetric efficiency of the VDSC is directly proportional to the PSL due to the constant absolute clearance at different Piston Stroke lengths. When the air conditioning load keep constant, the PSL and displacement of the VDSC are regulated to meet the air conditioning load at different compressor rotary speeds or vehicle speeds. When the air conditioning load changes gradually, the PSL has a number of small step changes so that the refrigerating capacity of the VDSC can well fit the air conditioning load. When the compressor rotary speed changes abruptly, the Piston Stroke length, refrigerant mass flow rate, and other parameters change with a very short time delay to ensure a nearly constant refrigerating capacity of compressor.

  • Experimental investigation on the steady-state performance and Piston Stroke length control of a variable displacement wobble plate compressor
    Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2005
    Co-Authors: Changqing Tian, Xianting Li, Yunfei Liao
    Abstract:

    The aim of this paper is to find out the steady-state performance and Piston-Stroke-length control behaviour of a variable displacement wobble-plate compressor for an automotive air-conditioning system by experimental investigation. First, a new method and device to measure the Piston Stroke length of the variable displacement compressor has been developed, with which the test bench for the variable displacement compressor has been set up. Second, the steady-state performance of the variable displacement compressor, such as the relative volumetric efficiency and the relative isentropic efficiency at partial Piston Stroke length, has been obtained. The influence of the work condition and compressor rotary speed on the relative volumetric efficiency can be neglected according to the test data. Finally, the critical wobble-plate case pressure is proposed in this paper to judge whether the Piston Stroke length will change or not. The critical wobble-plate case pressure when the Piston Stroke length decreases is greater than that when the Piston Stroke length increases, which is less influenced by the Piston Stroke length itself from the test data. The higher the compressor discharge pressure or rotary speed, the greater the critical wobble-plate case pressure. The Piston Stroke length can be adjusted automatically along with the air-conditioning load when the compressor rotary speed or air conditioning load changes.

  • Instability of automotive air conditioning system with a variable displacement compressor. Part 1. Experimental investigation
    International Journal of Refrigeration-revue Internationale Du Froid, 2005
    Co-Authors: Changqing Tian, Xinjiang Yang, Xianting Li
    Abstract:

    A test system is built first in order to investigate the instability of the automotive air conditioning (AAC) system with a variable displacement compressor (VDC), and hunting phenomena caused by the large external disturbance in the AAC system with a VDC and a thermal expansion valve, and in the AAC system with a VDC and a fixed-area throttling device are investigated experimentally in part 1 of this paper. The experimental results indicate that there also exist the hunting phenomena in the AAC system with a fixed-area throttling device. The system stability is found to be dependent on the direction of the external disturbance, and the system is apt to cause hunting when the condensing pressure decreases excessively since it may cause two-phase state at the throttling device inlet and make a large disturbance to the system. The Piston Stroke length will oscillate only when the oscillation amplitudes of forces acting on the wobble plate are great enough, otherwise the Piston Stroke length will be kept invariable, and then the system instability rule is also suitable for the AAC system with a fixed displacement compressor. From the experimental results, it is concluded that the two-phase flow at the throttling device inlet or at the evaporator outlet is the necessary condition but not sufficient condition for system hunting. Finally, a new concept, conservative stable region, is proposed based on the experimental results and theoretical analysis.

  • Transient behavior evaluation of an automotive air conditioning system with a variable displacement compressor
    Applied Thermal Engineering, 2005
    Co-Authors: Changqing Tian, Xianting Li
    Abstract:

    In order to simulate the transient behavior of the automotive air conditioning (AAC) system with a variable displacement wobble plate compressor (VDC), a dynamic model which is consisted of a VDC, a finned tube evaporator, a parallel flow type condenser, a cross and absorptive charge H type thermal expansion valve, and a suction pipe is developed. Both the simulation results of control valve and experimental data of VDC indicate that transient process inside VDC can be ignored and the steady state model of VDC can be used in the dynamic simulation of AAC system. The method to calculate the variation of Piston Stroke length is proposed in the numerical solution procedure for dynamic simulation of AAC system. A test system is built with original components from an actual AAC system and the dynamic simulation results are compared with the experimental data. It is shown that the predicted results with the dynamic model agree well with the experimental data. Further simulation results show that: (1) whether the Piston Stroke length changes or not is determined by not only the changing values but also the changing direction of external parameters in the AAC system; (2) the variation of Piston Stroke length usually has a time lag when the external parameter varies; (3) there is a greater counter-regulation for the refrigerating capacity and compressor power consumption when the compressor rotary speed changes suddenly due to the adjustment of Piston Stroke length, which is different from the AAC system with a fixed displacement compressor.

  • Instability of automotive air conditioning system with a variable displacement compressor. Part 1. Experimental investigation
    International Journal of Refrigeration, 2005
    Co-Authors: Changqing Tian, Chunpeng Dou, Xinjiang Yang, Xianting Li
    Abstract:

    A test system is built first in order to investigate the instability of the automotive air conditioning (AAC) system with a variable displacement compressor (VDC), and hunting phenomena caused by the large external disturbance in the AAC system with a VDC and a thermal expansion valve, and in the AAC system with a VDC and a fixed-area throttling device are investigated experimentally in part 1 of this paper. The experimental results indicate that there also exist the hunting phenomena in the AAC system with a fixed-area throttling device. The system stability is found to be dependent on the direction of the external disturbance, and the system is apt to cause hunting when the condensing pressure decreases excessively since it may cause two-phase state at the throttling device inlet and make a large disturbance to the system. The Piston Stroke length will oscillate only when the oscillation amplitudes of forces acting on the wobble plate are great enough, otherwise the Piston Stroke length will be kept invariable, and then the system instability rule is also suitable for the AAC system with a fixed displacement compressor. From the experimental results, it is concluded that the two-phase flow at the throttling device inlet or at the evaporator outlet is the necessary condition but not sufficient condition for system hunting. Finally, a new concept, conservative stable region, is proposed based on the experimental results and theoretical analysis. © 2005 Elsevier Ltd and IIR. All rights reserved.

Changqing Tian - One of the best experts on this subject based on the ideXlab platform.

  • Piston Stroke Design Optimization for Linear Compressor
    Advanced Materials Research, 2011
    Co-Authors: Li Qin Zhang, Guo Hong Peng, Changqing Tian
    Abstract:

    This paper presents a method of Piston Stroke design optimization for linear compressor to get high efficiency.Two linear compressor prototypes were designed and developed with the same discharge volumes and different Piston Strokes to compare the performance. The prototypes were operated without air load to measure the friction damping coefficient firstly. Then the prototypes were operated with air load of 0.7MPa discharge pressure. The experimental result shows that the input power of the prototype with longer Stroke is lower than that of the prototype with shorter Stroke although the discharge volume, the friction damping coefficient and the frequency ratio of these two prototyps are almost the same. The iron and coil loss of the prototype with longer Stroke is lower than that with shorter Stroke, while the mechanical loss of the prototype with longer Stroke is larger than that with shorter Stroke. According to the results of the performance analysis, a design optimization model for Piston Stroke is developed to make the energy loss be the least. Through this design optimization model, acquire the optimal Piston stoke of the linear compressor on the same conditions with the experiment. The optimization results agree well with the experimental results.

  • Experimental investigation on the characteristics of variable displacement swash plate compressor
    Applied Thermal Engineering, 2009
    Co-Authors: Changqing Tian, Li Qin Zhang, Hongbo Xu, Xianting Li
    Abstract:

    Abstract This paper is on a new device developed to measure the Piston Stroke length (PSL) of the variable displacement swash plate compressor (VDSC), with which the test bench for the VDSC and test system for automotive air conditioner with VDSC is constructed. The volumetric efficiency, PSL and displacement control, and transient behavior along with air conditioning load or compressor rotary speed are investigated experimentally. The experiment results show that the volumetric efficiency of the VDSC is directly proportional to the PSL due to the constant absolute clearance at different Piston Stroke lengths. When the air conditioning load keep constant, the PSL and displacement of the VDSC are regulated to meet the air conditioning load at different compressor rotary speeds or vehicle speeds. When the air conditioning load changes gradually, the PSL has a number of small step changes so that the refrigerating capacity of the VDSC can well fit the air conditioning load. When the compressor rotary speed changes abruptly, the Piston Stroke length, refrigerant mass flow rate, and other parameters change with a very short time delay to ensure a nearly constant refrigerating capacity of compressor.

  • Experimental investigation on the steady-state performance and Piston Stroke length control of a variable displacement wobble plate compressor
    Proceedings of the Institution of Mechanical Engineers Part D: Journal of Automobile Engineering, 2005
    Co-Authors: Changqing Tian, Xianting Li, Yunfei Liao
    Abstract:

    The aim of this paper is to find out the steady-state performance and Piston-Stroke-length control behaviour of a variable displacement wobble-plate compressor for an automotive air-conditioning system by experimental investigation. First, a new method and device to measure the Piston Stroke length of the variable displacement compressor has been developed, with which the test bench for the variable displacement compressor has been set up. Second, the steady-state performance of the variable displacement compressor, such as the relative volumetric efficiency and the relative isentropic efficiency at partial Piston Stroke length, has been obtained. The influence of the work condition and compressor rotary speed on the relative volumetric efficiency can be neglected according to the test data. Finally, the critical wobble-plate case pressure is proposed in this paper to judge whether the Piston Stroke length will change or not. The critical wobble-plate case pressure when the Piston Stroke length decreases is greater than that when the Piston Stroke length increases, which is less influenced by the Piston Stroke length itself from the test data. The higher the compressor discharge pressure or rotary speed, the greater the critical wobble-plate case pressure. The Piston Stroke length can be adjusted automatically along with the air-conditioning load when the compressor rotary speed or air conditioning load changes.

  • Instability of automotive air conditioning system with a variable displacement compressor. Part 1. Experimental investigation
    International Journal of Refrigeration-revue Internationale Du Froid, 2005
    Co-Authors: Changqing Tian, Xinjiang Yang, Xianting Li
    Abstract:

    A test system is built first in order to investigate the instability of the automotive air conditioning (AAC) system with a variable displacement compressor (VDC), and hunting phenomena caused by the large external disturbance in the AAC system with a VDC and a thermal expansion valve, and in the AAC system with a VDC and a fixed-area throttling device are investigated experimentally in part 1 of this paper. The experimental results indicate that there also exist the hunting phenomena in the AAC system with a fixed-area throttling device. The system stability is found to be dependent on the direction of the external disturbance, and the system is apt to cause hunting when the condensing pressure decreases excessively since it may cause two-phase state at the throttling device inlet and make a large disturbance to the system. The Piston Stroke length will oscillate only when the oscillation amplitudes of forces acting on the wobble plate are great enough, otherwise the Piston Stroke length will be kept invariable, and then the system instability rule is also suitable for the AAC system with a fixed displacement compressor. From the experimental results, it is concluded that the two-phase flow at the throttling device inlet or at the evaporator outlet is the necessary condition but not sufficient condition for system hunting. Finally, a new concept, conservative stable region, is proposed based on the experimental results and theoretical analysis.

  • Transient behavior evaluation of an automotive air conditioning system with a variable displacement compressor
    Applied Thermal Engineering, 2005
    Co-Authors: Changqing Tian, Xianting Li
    Abstract:

    In order to simulate the transient behavior of the automotive air conditioning (AAC) system with a variable displacement wobble plate compressor (VDC), a dynamic model which is consisted of a VDC, a finned tube evaporator, a parallel flow type condenser, a cross and absorptive charge H type thermal expansion valve, and a suction pipe is developed. Both the simulation results of control valve and experimental data of VDC indicate that transient process inside VDC can be ignored and the steady state model of VDC can be used in the dynamic simulation of AAC system. The method to calculate the variation of Piston Stroke length is proposed in the numerical solution procedure for dynamic simulation of AAC system. A test system is built with original components from an actual AAC system and the dynamic simulation results are compared with the experimental data. It is shown that the predicted results with the dynamic model agree well with the experimental data. Further simulation results show that: (1) whether the Piston Stroke length changes or not is determined by not only the changing values but also the changing direction of external parameters in the AAC system; (2) the variation of Piston Stroke length usually has a time lag when the external parameter varies; (3) there is a greater counter-regulation for the refrigerating capacity and compressor power consumption when the compressor rotary speed changes suddenly due to the adjustment of Piston Stroke length, which is different from the AAC system with a fixed displacement compressor.

Eckhard A. Groll - One of the best experts on this subject based on the ideXlab platform.

  • Modeling of an Oil-Free Carbon Dioxide Compressor Using Sanderson-Rocker Arm Motion (S-RAM) Mechanism
    IOP Conference Series: Materials Science and Engineering, 2015
    Co-Authors: Bin Yang, Orkan Kurtulus, Eckhard A. Groll
    Abstract:

    A simulation model to predict the performance of a prototype CO2 compressor is presented. This prototype compressor employs the Sanderson-Rocker Arm Motion (S-RAM) mechanism, which converts the rotary motion of the shaft into a linear reciprocating motion of the cylinders. The Piston Stroke can be variable by changing the incline angle between the connecting rod and compressor main shaft centerline. The compressor model is mainly composed of two main sub-models simulating the kinematics of the drive mechanism and the compression process. A valve sub-model is included in the compression process model.

  • Sensitivity Analysis of a Comprehensive Model for a Miniature-Scale Linear Compressor for Electronics Cooling
    International Journal of Refrigeration-revue Internationale Du Froid, 2013
    Co-Authors: Craig R. Bradshaw, Eckhard A. Groll, Suresh V. Garimella
    Abstract:

    A comprehensive model of a linear compressor for electronics cooling was previously presented by Bradshaw et al. (2011). The current study expands upon this work by first developing methods for predicting the resonant frequency of a linear compressor and for controlling its Piston Stroke. Key parameters governing compressor performance – leakage gap, eccentricity, and Piston geometry – are explored using a sensitivity analysis. It is demonstrated that for optimum performance, the leakage gap and frictional parameters should be minimized. In addition, the ratio of Piston Stroke to diameter should not exceed a value of one to minimize friction and leakage losses, but should be large enough to preclude the need for an oversized motor. An improved linear compressor design is proposed for an electronics cooling application, with a predicted cooling capacity of 200 W a cylindrical compressor package size of diameter 50.3 mm and length 102 mm.

  • Bowtie Compressor with Novel Capacity Modulation Part 1: Design Description and Model Development
    2011
    Co-Authors: Eckhard A. Groll
    Abstract:

    A novel refrigeration compressor with an integrated method of capacity modulation for use in domestic refrigerators/freezers is proposed and analyzed here. The compressor is called bowtie compressor due to its two sector-shaped, opposing compression chambers forming a bowtie. The bowtie compressor modulates the cooling capacity by changing the Piston Stroke without changes of the clearance volume for better thermodynamic efficiency. The new compressor includes a unique off-center-line mechanism so that the Piston Stroke can be varied without changes in motor rotation. To investigate the feasibility of the proposed compressor, a simulation model has been developed. A detailed description of the bowtie compressor and its simulation model are presented in this paper.

  • Bowtie Compressor with Novel Capacity Modulation Part 2: Model Validation and Parametric Studies
    2011
    Co-Authors: Eckhard A. Groll
    Abstract:

    A novel refrigeration compressor with an integrated method of capacity modulation for use in domestic refrigerators/freezers is proposed and analyzed here. The compressor is called bowtie compressor due to its two sector-shaped, opposing compression chambers forming a bowtie. The bowtie compressor modulates the cooling capacity by changing the Piston Stroke without changes of the clearance volume for better thermodynamic efficiency. The new compressor includes a unique off-center-line mechanism so that the Piston Stroke can be varied without changes in motor rotation. To investigate the feasibility of the proposed compressor, a simulation model has been developed. The validation of the simulation methodology and parametric studies to see how the proposed compressor performance can be improved are presented in this Part II paper.

  • Feasibility study of a bowtie compressor with novel capacity modulation
    International Journal of Refrigeration-revue Internationale Du Froid, 2007
    Co-Authors: Eckhard A. Groll
    Abstract:

    A novel refrigeration compressor with an integrated method of capacity modulation for use in domestic refrigerators/freezers is proposed and analyzed here. The compressor is called bowtie compressor due to its two sector-shaped, opposing compression chambers forming a bowtie. The bowtie compressor modulates the cooling capacity by changing the Piston Stroke without changes of the clearance volume for better thermodynamic efficiency. The new compressor includes a unique off-center-line mechanism so that the Piston Stroke can be varied without creating an extra clearance volume. To investigate the feasibility of the proposed compressor, a simulation model has been developed. A detailed description of the bowtie compressor and its simulation model are presented in this paper. In addition, parametric studies have been carried out to see how the proposed compressor performance can be improved.

Jean Lebrun - One of the best experts on this subject based on the ideXlab platform.

  • Testing and modelling of an automotive wobble plate compressor
    International Journal of Refrigeration-revue Internationale Du Froid, 2008
    Co-Authors: Cristian Cuevas, Eric Winandy, Jean Lebrun
    Abstract:

    Abstract Wobble plate compressors are well used in air conditioning for high-class automobiles. They allow continuous control by automatic adjustment of the Piston Stroke, to keep the low pressure above a certain limit. Here an externally controlled wobble plate compressor is analyzed experimentally through its isentropic and volumetric effectivenesses and control characteristics. Compressor effectivenesses depend mainly on the compressor speed and pressure ratio: there is obtained, for example, isentropic and volumetric effectivenesses of 0.65 and 0.8 for a pressure ratio of 4 at 1000 rpm and 0.4 and 0.35 for the same pressure ratio at 4000 rpm. This degradation is attributed to the increasing of the supply pressure drop. The “lubricant” (oil + dissolved refrigerant) mass flow rate is obtained by minimization of the residuals of the thermal balances on the compressor, condenser and evaporator. Here an important oil-flow circulation is obtained: between 9.5% and 12.5% of the refrigerant flow rate. A special displacement sensor is used to measure instantaneous Piston Stroke and to relate it to overall compressor performance. This measurement is then compared with the results obtained with a semi-empirical model, which is able to predict, in part load, the compressor displacement. The model predicts the displacement ratio with deviations that vary between −14.5% and +8.1%.

  • Testing and modelling of an automotive wobble plate compressor
    International Journal of Refrigeration, 2008
    Co-Authors: Carlos Cuevas, Eric Winandy, Jean Lebrun
    Abstract:

    Wobble plate compressors are well used in air conditioning for high-class automobiles. They allow continuous control by automatic adjustment of the Piston Stroke, to keep the low pressure above a certain limit. Here an externally controlled wobble plate compressor is analyzed experimentally through its isentropic and volumetric effectivenesses and control characteristics. Compressor effectivenesses depend mainly on the compressor speed and pressure ratio: there is obtained, for example, isentropic and volumetric effectivenesses of 0.65 and 0.8 for a pressure ratio of 4 at 1000 rpm and 0.4 and 0.35 for the same pressure ratio at 4000 rpm. This degradation is attributed to the increasing of the supply pressure drop. The "lubricant" (oil + dissolved refrigerant) mass flow rate is obtained by minimization of the residuals of the thermal balances on the compressor, condenser and evaporator. Here an important oil-flow circulation is obtained: between 9.5% and 12.5% of the refrigerant flow rate. A special displacement sensor is used to measure instantaneous Piston Stroke and to relate it to overall compressor performance. This measurement is then compared with the results obtained with a semi-empirical model, which is able to predict, in part load, the compressor displacement. The model predicts the displacement ratio with deviations that vary between -14.5% and +8.1%. © 2007 Elsevier Ltd and IIR.

D. Kirejchick - One of the best experts on this subject based on the ideXlab platform.

  • Slider-link driven compressor (I). Mathematical model
    2016
    Co-Authors: V Dagilis, L Vaitkus, D. Kirejchick
    Abstract:

    The presented mathematical model is targeted for the optimization of slider-link driven compressor, i.e. for the selection of such geometrical parameters (Piston Stroke to diameter ratio, Piston eccentricity, clearance between the Piston and the cylinder, etc.), which will ensure the highest efficiency.

  • Mathematical model of slider-link driven compressor. II. Simulation results.
    2006
    Co-Authors: V Dagilis, L Vaitkus, D. Kirejchick
    Abstract:

    This paper describes methods for solving equations of the mathematical model of slider-link driven compressor, presented in the first part of the paper (see this Bulletin, reference 2007-1059). The model is used to calculate dynamic behaviour of movable machine elements, constraint forces, friction forces and unbalanced inertia forces. Simulation results compared to experimental measurements of rotation speed, good agreement between numerical and experimental data has been obtained. The model is used for analysing the influence of various parameters, such as Piston eccentricity, Piston Stroke to diameter ratio, displacement on compressors performance. Even though the model gives detailed description of dynamic behaviour and mechanical losses, the more detailed thermodynamic characterization of the compressor should be developed for overall compressor optimization.