Research On Heat Transfer And Thermal Resistance Performance Of Open-hole Shutter Finned Heat Exchanger For Vehicle

As an important part of automobile air conditioning system,the parallel flow heat transfer is directly related to the performance of automobile air conditioning.The shutter fin with compact structure and high heat transfer efficiency is widely used in parallel flow heat exchangers for vehicles.In this paper,theoretical analysis,experimental testing and numerical simulation are used to analyze the structural parameters affecting the heat transfer and flow resistance performance from the aspect of the type of louver fins.The numerical model of the traditional louver fin was established,and the reliability and rationality of the simulation calculation method were verified by the comparative analysis of the three conclusions of simulation calculation value,empirical correlation value and experimental value.Furthermore,the open-hole finned structure is proposed and a three-dimensional numerical model is established.The heat transfer and flow resistance performance of the structure are studied from the aspects of the number of holes,the diameter of holes and the arrangement of holes in the range of Reynolds number from 150 to 450.Compared with the traditional fin and the open-hole fin,the flow performance of the open-hole shutter fin is better.The main conclusions are as follows:(1)The results show that the simulation value,empirical correlation value and experimental value of traditional louver fins are compared:The maximum error between the traditional louver fin heat transfer factors is 11.9%,and the maximum error between the friction factors is 11.3%.The error between the three factors conforms to the allowable error range,which proves that the simulation model established in this paper is feasible.(2)The comparison of the comprehensive performance between the fin of the open-hole shutter and that of the traditional shutter shows that the heat transfer factor of the fin of the open-hole shutter increases by 4.16-5.52%;The friction factor decreased by 12.38-16.31% and the comprehensive performance factor increased by 8.3-10.97%.Therefore,the wing of the open-hole shutter greatly reduces the flow resistance on the air side.(3)Opening type shutter fin other structure under the condition of invariable parameters,the number of openings of the louver fins is 3,the equivalent diameter of the holes is 0.1mm,and the comprehensive performance factor of the opening fins is improved by 11.57-16.71%.When the fins with 3 holes are arranged,the heat transfer effect of the fins with straight holes is better than that of the fins with triangular holes.In addition,with the same equivalent diameter,the heat transfer performance of the fins with round holes,square holes and equal-triangle holes was compared.The heat transfer performance of the fins with round holes was better,and the increase of the comprehensive performance factor was 5.3-8.6%.