喷射特征的双级压缩系统压缩过程及喷射参数耦合特性

Compression Process and Coupling Properties of Injection Parameters for Two-stage Compression System with Injection

以2台转子压缩机构成的双级压缩系统为研究对象,构建具有喷射特征的双级压缩系统仿真模型,并利用实验对模型进行了验证。基于模拟和实验分析了喷射特征参数的耦合关系、级间参数形成过程和级间喷射对双级压缩过程的影响。模拟结果显示:喷射量和喷射工质比焓是以中间换热器为约束的一对耦合参数,喷射工质比焓随着喷射量的增大具有先略微增大而后逐渐减小的变化趋势。中间喷射特征参数对级间参数具有显著影响;喷射工质比焓决定着系统级间各状态点变化的方向,而喷射量决定系统级间各状态点改变的程度;在工况和喷射特征参数恒定的条件下,中间喷射过程将近似一个“等压过程”过程。

A two-stage compression system composed of two rotary compressors was used as the research object to establish a simulation model of the two-stage compression system with injection,and the model was validated by experiments.Based on the simulation and experiments,the coupling relations among the injection parameters,the formation process of the inter-stage parameters and the effects of the inter-stage injection on the two-stage compression process were analyzed.The simulation results show that the mass flowrate and specific enthalpy of the injection refrigerant are a pair of coupling parameters with the intermediate heat exchanger as the constraint.The specific enthalpy of the injection refrigerant first increased and then decreased gradually as the mass flowrate of the injection refrigerant increased.The intermediate injection characteristic parameters have significant impact on inter-stage parameters.The specific enthalpy of the injection refrigerant determines the direction of the change at each interstage state point of the system,whereas the mass flowrate of the injection refrigerant determines the degree of the change in each inter-stage state point of the system.Under the condition of constant operating conditions and injection characteristic parameters,the intermediate injection process approximates an“isobaric mixing”process.