Phase Equilibrium And Characteristics Research For Non-azeotropic Mixed-refrigerant Auto Cascade Refrigerator

The thesis aims at the research of non azeotropic auto cascade refrigeration System. Onthe basis of the study of phase equilibrium and thermodynamic properties of non azeotropicmixed refrigerant, a method of analyzing non azeotropic mixed refrigerant auto cascaderefrigerator has been built in the thesis. From the discussion, a high thermodynamicefficiency refrigeration system under150℃has been found.In this paper, the RKS80equation has been chosen to the research of thermodynamicproperties of non azeotropic mixed refrigerant. The iterative calculation method has beenintroduced to obtain the parameters in the equation, including Z、m and n. On the basis of thehybrid rules revised by Redlich, the binary interaction coefficients is fitted by quering theliterature. According to the method of equation of state, the mathematical and physicsmodels have been established, meanwhile, the thesis attempts to conduct an exploration ofthe calculation method. The thermodynamic properties have been calculated using the cubicequation of state, the calculation results are shown as the enthalpy temperature diagram andtable.From the relation between thermodynamic properties of refrigerant mixtures andperformance of refrigeration cycle of view, the component of the refrigerant mixture isinvolved in the thesis. Compared with different components in the system, the optimumcomponent has been found. With the same way, the optimum pressure parameter has beenchosen.Compared with the datas calculated in the NIST databases, the parameters calculated inthis thesis are reliable. Taking into account the lack of experimental research, the thesis alsoprovide some useful suggestions for next stage to study the thermodynamic properties ofrefrigeration mixtures and optimize the performance of auto cascade refrigeration system.