Improvement And Optimization Of Welding Structure Of Aluminum Plate-fin Heat Exchanger Of Hydraulic Pile Driver

In this paper,the heat exchanger of the pile driver is taken as the research object.In view of the problem that the weld joint of the heat exchanger is prone to fatigue cracking,the fluid flow process inside the heat exchanger and the fatigue strength under the alternating pressure of the heat exchanger are analyzed by fluid-solid coupling analysis.Study,analyze the cause of failure and fatigue-prone position of the weld joint,and combine the numerical simulation results to optimize the design of the welded structure of the heat exchanger seal and the structure of the oil chamber.The main research work and results of this article are as follows:(1)Three-dimensional numerical simulation of the velocity field and pressure field of the cooling medium was carried out by Fluent,and the velocity vector diagram and pressure cloud diagram during fluid movement were obtained.From the figure,the peak value of the pressure load of the cooling medium on the inner wall surface of the heat exchanger is 1.97 Mpa.(2)Through the Ansys Static Structural simulation module,combined with the Fluent fluid simulation data,the fluid-structure coupling analysis of the elastoplastic performance of the heat exchanger is performed,and the total deformation cloud diagram and equivalent stress cloud diagram of the heat exchanger are obtained.On this basis,combined with the SN fatigue strength curve of the material and the time load curve,the fatigue life analysis and prediction of the heat exchanger was carried out.It was concluded that the theoretical minimum value of the fatigue life of the heat exchanger was 91896 cycles,and the lowest point of the fatigue life was located at Oil inlet oil compartment.(3)In view of the above problems,two suggestions for improvement were proposed,and the rationality was verified by means of simulation.In order to solve the problem of seal welding structure failure,it is optimized,and the optimal size structure of seal pressure capacity is explored by fitting the structural performance curve.Aiming at the problem that the pressure in the oil chamber is too high,which leads to fatigue failure of the weld seam,a structure of the oil chamber with baffles is proposed.The simulation analysis of the heat exchanger after the structure optimization is carried out.Through comparative analysis,it can be concluded that the minimum value of the fatigue life of the heat exchanger is increased from 91896 cycles to 9.5082e5 cycles,and the theoretical service life is greatly improved.(4)The new product has been tested by blasting test,and the blasting limit pressure value is 4.9Mpa.In this paper,the finite element analysis software is used as the analysis tool,and the blasting test is used as the verification.The fatigue performance of the heat exchanger under alternating pressure is studied.At the same time,some optimization suggestions are proposed for the research results,and the fatigue life of the heat exchanger is studied.It has certain reference significance.