Theoretical And Experimental Study Of The Reverse-Brayton Heat Pump Cycle With Two-Phase Non-Azeotropic Refrigerants

The phase change of non-azeotropic refrigerants in evaporator and condenser is a isobaric&non-isothermal process. And the heat source in the two heat exchanger is also non-isothermal. In the view of thermodynamics, if the heat exchange processes of the refrigerants and the heat source match well, the irreversibility of the heat exchange process will be much more less and the efficiency of the cycle will be higher. Utilizing the non-azeotropic refrigerants and the two phase expanse work of the expander, this thesis, theoretically and experimentally, analyzes and explores thoroughly the cycyle performance in the heat pump system of the Reveser-Brayton Cycle.The T-S phase diagram of working substance is very important for cycle simulation, design and analysis. The relative location of cycle process lines and the saturation curve of the T-S phase diagram playes an important role in the design of the equipment and operation of the system. This thesis analyzes the shape of the saturation curve of some working substances' T-S phase diagram, especially the shape of the saturated vapor line.To take advantage of the temperature glide matching of working substances and heat resources is an very importment reason of using non-azeotropic refrigerants. If the glide is small, the advantage is difficult to be taken, and if the glide is too big, the irreversibility of the heat exchange process would be much more bigger either. This thesis also analyzes the temperature glide of some non-azeotropic refrigerants, and the characteristic of enthalpy change during the phase change process, which has much correlativity with the temperature glide.In order to attain the nature of this research object, by the thermodynamic analysis and selecting refrigerants from the view of thermodynamic, it, used RKS equation ofBSTRACTstate, carried out simulating the cycle with multiplex non-azeotropic refrigerants, and discussed in details the impacts of many restriction on the cycle performance, which involved the component of the refrigerants etc.The experimental study verified the theoretical results. Ultimately, a few important conclusions were obtained and some problems were found, which provide the direction for further study.