Numerical Study Of The Influence Of The Structure Of The Offset Fin On The Heat Transfer Performance

The plate fin heat exchanger with offset fin is used for lubricating oil heat transfer in aero engine lubricating oil system because of its high heat transfer efficiency,compact structure small volume and light weight.At present,most of the offset fin s are used in the heat transfer of the medium with low viscosity and low Prandt,and most of the fins have a larger hydraulic diameter,but the lubricating oil in the aero engine has the characteristics of high temperature,high viscosity and high Prandt number,and the hydraulic diameter of the misplaced fin in the oil heat exchanger is small.Therefore,this paper uses high temperature oil as the medium to simulate the offset fins of small hydraulic diameter,and researchs the influence of structural parameters on the heat transfer performance,provides a theoretical reference for the application of the aero engine misaligned fin and plate fin heat exchanger.The numerical simulation and verification of the misplaced fin are carried out in this paper.The v~2-f model is confirmed as the simulation model.Compared with the experimental data,the average error of the temperature difference is 5.64%,and average error of the pressure drop is 3.76%.On this basis,the flow field of the offset fin is studied.According to the control variable method,the structural parameters(fin spacing,fin height,fin length,fin thickness,shape angle and flow angle)are changed to be simulated,and the conclusion is drawn by comparing the parameters and performance factors in the flow field(flow line distribution,vorticity,temperature,velocity and local convective heat transfer coefficient).It is concluded that the fin spacing and fin length strengthen the heat transfer by destroying the boundary layer,increasing the heat transfer area and the disturbance,the fin thickness,tooth profile angle and flow angle strengthen the heat transfer by destroying the boundary layer and increasing the disturbance,fin height strengthens the heat transfer by increasing the heat transfer area;with the decrease of s and l,the increase of h,t,a andβ,the heat transfer performance and resistance performance of fin gradually increase;with the decrease of s and h,the increase of t,a andβ,the comprehensive performance of fin increases gradually increase;the comprehensive performance of fin is optimal when the l=4mm.The influence of structural parameters on fin performance is obtained by one-way factor ANOVA.The influence of tooth profile angle and flow angle on the heat transfer performance of the misaligned fin is the most significant,followed by fin height,and the rest structure is relatively weak.Finally,the empirical correlation between the j factor and the f factor in the scope of the study is established by using the simulated data.