Mathematical model of heat pumps' coaxial evaporator with distributed parameters

Abstract

The aim of this article is to create a very precise mathematical model with distributed parameters of the heat pumps' coaxial evaporator in order to examine the behavior of evaporator in the steady-state operation mode. The mathematical model consists of the balance equations, the equations of viscous friction coefficient, the convective heat transfer, and the state equation of refrigerant R134a. The boundary conditions, which are the thermal-expansion valve and the compressor, in this work, have not yet been taken into account. It is the task and the goal of the next article. For the solution of mathematical model an iterative numerical procedure was applied. Simulation results were obtained in numerical form and are presented graphically. The ‘new’ in this paper: implanted the Kandlikar's evaporative heat transfer coefficient as a function of vapor quality, applied the viscous friction coefficient of the refrigerant according to Friedel and state equations of R134a according to Martin-Hou. In addition, using the new mathematical model simulated the behavior of coaxial evaporator.