Experiment And Refrigerant Charge Study On Airborne Vapor Cycle Refrigeration System

With the increase electronic equipment and the heat load of modern aircraft,airborne vapor cycle refrigeration system is more in line with the future development direction of aircraft environmental control system.At present,the integrated design,simulation analysis and experimental research of quasi-two-stage vapor cycle refrigeration system are not perfect in our country,and the research on the influence,matching and monitoring of refrigerant charge for the system needs to be enriched.This paper focuses on the above weaknesses,the main contents are as follows:(1)This paper designed and built an airborne quasi-two-stage compression vapor cycle refrigeration system.Based on ANSYS software platform,a model analysis,a random vibration analysis and a thermal stress analysis were carried out.The structural reliability of the system under airborne dynamic and static loads was checked.(2)Experiments about airborne vapor cycle refrigeration system were carried out.The effects of refrigerant charge,airborne conditions and relative vapor supply volume on refrigeration performance were analyzed.The optimum refrigerant charge and relative vapor supply were determined,and the universality of this charge value with different working conditions was proved.Also the influence of refrigerant charge and compressor frequency on system operating parameters were summarized.(3)Based on MATLAB/Simulink,the simulation model of airborne vapor cycle refrigeration system was built.Relationships between the flow rate of condenser and the quality of refrigerant was fitted,the research scope is expanded,and a database of system operating parameters corresponding to refrigerant charge was established.(4)The characterization parameters of refrigerant charge were found by principal component analysis and correlation analysis.On this basis,using physical model and BP neural network,a virtual refrigerant charge(VRC)sensor of airborne vapor cycle refrigeration system was established and revised.By comparing and analyzing,the optimal VRC-PCA-BP model was determined,also the performance of the VRCsensor was tested to be reliable.In general,for the airborne vapor cycle refrigeration system,this study provided a technical reserve for the structural design and optimization,an effective method for the matching and optimization of refrigerant charge and relative vapor supply,a theoretical basis for the influence characteristics of refrigerant charge,an efficient mean for refrigerant charge monitoring and fault diagnosis of the system,and a good foundation for the control optimization and intelligent development.