Optimization Research On Design And Manufacturing Processes Of Electric Automobile Air Conditioning Heat Exchanger

In recent years, the automotive industry has been developed rapidly, however, with the depletion of the fossil fuel, the automobile has gradually entered into the era of "oil free", and the electric automobile came into being. The basis of the electric automobile’s higher driving range is the high efficiency of its air-conditioning, and the evaluation of air conditioning heat exchanger performance is the key to high efficiency air conditioning system. The micro channel heat exchanger has many advantages such as efficient, material-saving, environmental protection and lightweight, all the properties make it becomes the first choice of electric automobile air conditioning heat exchanger. According to the combination of numerical simulation and testing method, the optimally design on flow passage and brazing technology of "BDe6" electric automobile air conditioning heat exchanger is studied in detail in this paper.The main contents and results obtained in the research are as follows:1. The performance parameters on different conditions and processes of eight kinds of parallel flow heat exchanger were tested by TESCOR automobile air conditioning heat exchanger performance test bench. The heat exchange, refrigerant pressure drop, flow and export temperature of refrigerant were tested, and then the corresponding change curves were fitted based on the datas obtained in the experiment. The optimal flow ratio of "BDe6" electric automobile air conditioning heat exchanger is0.41:0.28:0.18:0.13.2. The effect and setting method of the brazing equipment and technological parameters were analyzed. Six groups of18samples were brazed with the temperature ranged from595℃to620℃. The quality of product joints were analyzed by air tightness inspection, artificial ASS acetic acid salt fog corrosion test and metallographic organization. According to the brazing results of six groups, the appropriate process parameters are:speed of net belt is800mm/min, spraying concentration of brazing flux is5%, hand painted strong concentration of brazing flux is23%, nitrogen purity is more than99.999%, drying temperature is230℃, and setting brazing temperature between610℃and615℃.3. The ANSYS finite element model of heat exchanger was established, according to the combination of numerical simulation and testing method, the reasonable experimental conditions were verified as follows:brazing time is1800seconds, and brazing temperature is610℃and615℃.4. Setting brazing temperature for660℃and speed of net belt to1200mm/min with ANSYS finite element model of optimized process parameters as the theoretical basis, which also obtains to meet the requirements of brazing joint. In this way the time of experiment is shortened, productive cost is reduced, and the productive efficiency is improved by1.5times.The above results demonstrate that using numerical simulation technology in the production of automobile air conditioning heat exchanger is feasible, which provides theory basis for the production and processing to similar structure parts. Research on the efficient brazing methods and scientific welding process combinations can reduce the costs of welding, which can also lower the costs of heat exchanger production, improve work efficiency, and promote the enterprise level. This paper has important theoretical significance and practical value to guide the actual production of electric automobile air conditioning heat exchanger.