Summary: | 碩士 === 遠東科技大學 === 機械工程研究所在職專班 === 107 === This study mainly used Visual Basic program to design a program to calculate the refrigeration cycle system and capillary length. First of all, the study begins with the description of the whole refrigeration cycle process and principle, understands the changes and correlations of the refrigerant under four states, and explains the selection conditions and limitations of the capillary, and explains the calculation method by formula. Research on why Visual Basic is used as a tool for analyzing the freezing cycle and calculating the capillary length.
In this study, we analyzed the difference between the refrigeration cycle R134a, the refrigerant R410A and the refrigerant R32 in the refrigeration cycle and the capillary length. In the refrigeration cycle, we calculated the refrigeration cycle parameters of the three refrigerants and plotted the pressure- enthalpy map with the parameters. The freezing effect, specific compression work and freezing coefficient of performance were comprehensively analyzed using the parameters of three refrigerants. In terms of capillary length calculation, we analyzed the changes of the length of the three refrigerants under different parameter settings. First, we know that during the superheat zone to the saturation point, the capillary length will still increase, and only the pure pressure drop phenomenon, other parameters It will not change with it. After calculation, it is found that the capillary inner diameter is reduced, the capillary length is relatively increased to reach a fixed pressure drop, and the capillary length increment is not always increased, but will slowly approach zero, indicating The length of the capillary no longer grows. Finally, a comparison of the capillary lengths of the three refrigerants at the same condensation and evaporation temperatures is performed. After the above analysis, the program designed in this study can help designers integrate the complex calculation of two-phase flow to make the calculation efficiency better, so as to facilitate the subsequent comprehensive analysis.
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