| In recent years,as a new type of efficient heat exchanger,micro-channel heat exchanger has gradually replaced the traditional heat exchanger,and it applications in automotive,electronics,refrigeration and other industries more and more widely.Micro-channel heat exchanger’s technology good or bad directly affects its heat transfer efficiency,so it is necessary to research on the technology of defect detection.This paper proposes a method of detecting the micro-channel heat exchanger process defect,to detect the existence of micro-channel heat exchanger internal blockage or internal leakage.The main contents of this paper include:(1)Through consulting relevant literature,learning the existing process defect detection methods of micro-channel heat exchanger.On this basis,put forward a method that through studying the pressure drop and flow characteristics of micro-channel heat exchanger to detect the presence of process defects.(2)Because of the diversity of micro-channel heat exchanger structure parameters,the quantitative relationship between the flow and pressure drop characteristics and process defect are also different,it is impossible to all physical measure.Therefore,to simulate the quantitative relationship between the flow and pressure drop characteristics and process defect of various micro-channel heat exchanger through simulation,in the production process,according to the predictable flow and pressure drop characteristics curve can judge the existence of internal defects.This paper with the model of MD020 micro-channel heat exchanger as the research object,have FLUENT simulation on the quantitative relationship between the flow and pressure drop characteristics and process defect.Firstly,studying the air flow distribution in each flat tube of micro-channel heat exchanger.The simulation results show that aerating a certain volume flow of air,flow distribution to each flat tube is uniform basically.(3)By FLUENT simulation,quantitative research the impact of pressure drop and flow characteristics caused by internal blockage.The simulation results obtain the pressure drop value when there are different number of internal blockages in different flow path,this value can be the reference for actual testing.(4)By FLUENT software simulation,quantitative and qualitative studying the impact of micro-channel heat exchanger pressure drop and flow characteristics caused by internal leakage.The simulation results show that internal leakage can cause micro-channel heat exchanger to reduce the pressure drop.When the radius of internal leakage gap in the first flow path is 2mm,the flow rate is about 600L/min,the pressure drop is reduced about 8.4k Pa.(5)In order to verify the simulation results,design a set of experimental system,and select the accessories reasonably.Having an experiment study on the impact of micro-channel heat exchanger pressure drop and flow characteristics caused by internal blockage.Within the scope of permissible error of sensor precision,the numerical value of the experimental results and the simulation results are basically identical.It shows that achieve the preanalysis of the quantitative relationship between the flow and pressure drop characteristics and process defect is feasible. |
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