Phase Equilibrium And Simulation Of Heat Exchanger For Mixed Refrigerant And Experimental Research

The thesis aimed at the research of five components of mixed refrigerants. From theoretical analysis, experiment simulation, experiment plant established, a discussion of thermodynamic properties from 120K to 180K have been held. From the discussion, a high thermodynamic efficiency and a reliable refrigeration system of the temperature field have been found.The RKS equations have been introduced to the study of thermodynamic properties of mixed refrigerants. From calculation m and n the two most important parameters have been obtained. The hybrid rules revised by Redlich are chosen and the computation mentality of factor of the interaction is initially introduced. By using the method of equation of state, the mathematical and physics models have been established; also have an exploration of the calculation method. With the method the phase equilibrium of mixed refrigerants have been calculated, also got refrigerant pressure, heat capacity, temperature, enthalpy and entropy. The calculation results are shown as the pressure-enthalpy diagram and table. The isotherm curves and the phase equilibrium curve formulated from the calculation results are presented in this pressure-enthalpy diagram. Those models provide important data for cycle analysis for the system using the kind of the mixture.On the basis of the study of phase equilibrium, a preliminary thermal analysis and numerical simulation to the thimble heat exchanger have been done. In the research process a simple model of mathematic, physics and heat exchange has been established to predict the temperature distribution, the coefficient of heat exchanger, the heat capacity, the Prandtl number distribution. The calculation can help understanding the operation condition of the heat exchanger.On the basis of theoretical research and numerical simulation, a single compress three stage auto cascade refrigeration system has been built in the thesis. Through the three parallel experiment, analyzed the experiment data and phenomenon, the temperature distribution curve has been got. The result validated that the whole inject qualities of refrigerant and the component percentage have great influence on the refrigeration system. The result also validated the correctness of simulation data of heat exchanger. The research results in this thesis will provide some useful suggestion for next stage to study the thermodynamic properties of refrigeration mixtures and optimize the performance of auto cascade refrigeration system.