Research On The Rough-peak Model Of Composite Metal Gaskets And The Flange Connection Structures

Pipes and pressure vessels usually use the form of flange gaskets,where the gasket acts to reduce the leakage of the sealing medium.Because the flange gasket structure is widely used in engineering equipment,the leakage of the sealing medium through the gasket is the main source,so the study on the sealing mechanism and the calculation model has important theoretical significance and practical engineering value.Researchers have carried out researches on the sealing characteristics of the flange gasket structure.The research mainly focuses on the macroscopic sealing mechanism of the connecting structure,the microscopic leakage model of the sealing area and the microscopic contact mechanics of the sealed rough area.Although the research on the sealing performance of flanged joints is relatively comprehensive,the existing leakage mechanism model and the prediction method contain a large number of experimental regression coefficients.In order to accurately predict the leakage rate of the flange gasket,this paper combined the flow simulation data of sealed rough area and the results of micro mechanical contact analysis,proposed a theoretical prediction model of the leakage rate which independent experimental regression coefficients.Firstly,MATLAB software was used to generate a random numerically rough surface whose rough surface profile obeys the Gauss distribution,the rough surface was imported into SOLIDWORKS software to build a rough surface 3D model.Then the 3D model of the rough seal contact area was simulated by using ANSYS simulation software.Finally,a large number of leakage rate simulation results were used to formulate the expression of the flow factor.The expression of the flow factor showed that the leakage rate of the connection structure was related to the parameters such as the sealing contact stress and the height of the sealing gap.In this project,a rough surface micro-roughened peak contact model was constructed based on contact mechanics theory.The contact model was analyzed by using ABAQUS finite element analysis software and the expression of the seal gap height on the seal contact stress and the seal factor was finalized based on the finite element analysis results.Based on the theory of porous,the results of fluid simulation and finite element analysis,a theoretical prediction model of the leakage rate was proposed.In order to verified the accuracy of the theoretical prediction model,this paper compared the experimental data of the lifting hole and the reference solid fuel cell in the project with the theoretical value of the leakage rate.Then,according to the theoretical prediction model of leakage rate,this paper analyzed the influencing factors of leakage rate and studied the effects of rough surface roughness,working temperature,sealing contact stress and the type of sealing medium on the sealing performance.The results of the study play an important role in the optimal design of the performance of the gasket seals for composite metal gaskets.