自复叠制冷系统压力和组分调节

热气旁通调节可有效排除高压对自复叠制冷系统的危害，但对混合工质的组分没有调节作用。针对三级自复叠制冷系统冷凝压力和排气温度较高的特点，提出了带两路旁通的4种压力和组分调控方式。热气旁通调节时冷凝压力周期性波动变化较大，电磁阀开启较频繁，系统开机70 min后才能达到稳定状态。二级相分离器气相出口旁通调节时冷量损失较严重，低温工质的冷量通过旁通管路排放到膨胀容器。一级相分离器气相出口调节和两个相分离器气相出口同时调节时制冷系统的性能很接近，系统开机30 min后即可达到稳定运行状态。通过对压缩机和蒸发器运行工况检测，一级相分离器气相出口调节和两个相分离器气相出口同时调节为较好的自动复叠制冷系统压力和组分调控方式。

Pressure and composition regulation of auto-refrigerating cascade system

The hot-gas bypass control can effectively eliminate the harm of high pressure on auto-refrigerating cascade system, but it is useless for the regulation of mixed refrigerant composition.The four kinds of pressure and composition adjustment method with two bypass was put forward in connection with the characteristics of higher condensing pressure and exhaust temperature of three-stage auto-refrigerating cascade cycle.The condensing pressure was changed in regular fluctuations and the solenoid valve was opened and closed frequently for the hot-gas bypass regulation, and the refrigeration system was stable after 70 min.The cold lost seriously for vapor outlet bypass adjustment of phase separator Ⅱ, and the cold of refrigerant was discharged to the reservoir through the bypass line.The performance of the refrigeration system was very close to the vapor outlet bypass adjustment of phase separator Ⅰ and two phase separators, and the refrigeration cycle was stable after 30 min.The vapor outlet bypass adjustment of phase separator Ⅰ and two phase separators were the better pressure and composition regulation method of auto-refrigerating cascade cycle according to the study of the operating conditions of compressor and evaporator.