Simulation And Design Of Heat Exchanger Of Automobile Air-conditioning

The work process of heat exchanger of automobile air-conditioning (HEAA) is a complicated process which mixes the heat transfer process and pressure drop process of both refrigerant flow and air flow, especially refrigerant phase convection flow process. Therefore heat dynamic performance's forecasting accurately is very important to the optimism design and energy consumption reduction of HEAA.At present, many research works use various distributed parameters models to establish HEAA' heat dynamic model, but those models don't often take account of the variation of local refrigerant thermo-physical properties which influence the performance of heat transfer pressure drop in the heat exchanger. In order to overcome the defect of existing models to improve the simulation accuracy and precision, a new HEAA' heat dynamic simulation model and structure optimal design method are proposed. The main contents are provided in this paper are as follows:The first chapter firstly expounds the research purpose and significance of this paper, secondly summarizes the current study situation of the development on the refrigerants thermal-hydraulic performance of heat transfer and pressure drop in micro/Mini-channels, the development on the air-side thermal-hydraulic performance of heat transfer and pressure drop for compact heat exchangers with multi-region louver fins, and the development on thermal-hydraulic performance simulation and optimism of compact condenser and evaporator, and thirdly introduces the main research contents of this paper.The second chapter, on the one hand, establishes the 1D-steady-state mathematic model of HEAA in the term of accurately simulating heat exchanger's performance, on the second hand, establishes refrigerant R134a thermo-physical model after investigating the thermo-physical parameters of refrigerant R134a which influence mathematic model of HEAA more while which influence less. The third chapter studies the common' performance characteristics of heat transfer and pressure drop in HEAA' condenser and evaporator based on the mathematic model of HEAA and the thermo-physical properties model of refrigerant R134a, and then establishes distributed parameters' general simulation models for three sorts of different phases by numeric method, this models work as foundations of design and simulation of both evaporator and condenser.The forth chapter, on the one hand, gives out some performance simulation result for single phase and two phases based on distributed parameters'general simulation models, on the other hand, discusses thermal-hydraulic performance simulation methods of compact condenser and evaporator after analysis the joint discipline of condenser and evaporator's three sorts of phases.The fifth chapter introduces HEAA's design method based on simulation, which is consisted by three step as follow:the physical structure schedule, preliminary design and evaluation, structure optimal design, and an instance integrating is given to illustrate the whole design process.The sixth chapter gives a summary about the main research contents of the full text of this paper, and gives an expectation on research works of HEAA's simulation and design in future.