Numerical Simulation Study On Delta-wing Louver Fin Structure In Vehicle Air Conditione

In order to implement the action of energy conservation and emission reduction and promote the development of the automotive industry,parallel flow heat exchangers finally stand out among many heat exchangers with their compact structure and high heat exchange efficiency.In this paper,the research focuses on the louver structure of the condenser side of the parallel flow heat exchanger,builds a fin model,uses numerical simulation methods to explore the factors affecting the heat transfer performance,and proposes an optimization method.The main contents are as follows:(1)First,establish a three-dimensional model of rectangular shutter fins,set appropriate boundary conditions,reasonably divide the grid to reduce the amount of calculation,and obtain a cloud map of temperature,speed and pressure of the shutter through simulation software.The simulated data is then summarized and the performance of the performance factor analysis model is calculated.The calculation results were verified by referring to the Chang and Wang correlation obtained by experts through a large number of experimental data and actual experimental tests.The results show that the error of the performance factors is less than 7%,which is within the allowable error range,so the shutter fin model in this paper is basically in line with the actual situation.(2)On the basis of the rectangular shutter fin model,in order to obtain better heat exchange performance,start from the air side fins and add triangular winglets.To construct a threedimensional model of the new fin structure,the boundary conditions and inlet velocity should be the same as the rectangular fin model for comparison.The simulation calculates the changes under different speed conditions,and compares and analyzes the cloud maps of the software simulation results of the two different fins.The results showed that the heat transfer factor of the delta airfoil shutter fin was 0.65%～3.94% higher than that of the rectangular shutter,and the friction factor was also increased by 2.78%～8.10%,from the results,the new fin did help to enhance the heat exchange effect,but also caused a lot of friction loss.(3)In the above research results,in order to further improve the heat transfer performance of the shutter fins and optimize the structural parameters of the delta wing fins,the angles selected in this paper are mainly the punch angle,number,bottom length and height of the delta wing.Since the number of different impact angles will limit the value range of the bottom length of the delta wing,this paper will start from the angle of impact to further optimize the height of the delta wing and the length of the bottom edge.Using the method of controlling variables,only changing a single parameter to compare how heat transfer and flow have changed.It is found that when the height of the delta wing occupies 55% of the fin gap,the heat transfer performance of the fin is better.The higher the number of delta wings,the longer the bottom length,resulting in higher heat exchanger performance.Finally,the optimal shutter parameters are: 12 wings,15° angle of impact,delta wing height h=0.4mm and bottom edge length a=0.8mm.Compared with the rectangular shutter fin,the heat transfer factor J of the improved new fin increased by 21.70%-25.02%,respectively.The increase rate of friction factor f was32.76%-39.35%,respectively.The increase rate of comprehensive factor EJF was 10.73%-12.04%,which significantly improved the heat exchange efficiency.