Study On Multi-objective Optimization Of Hydrodynamic Mechanical Seal Based On Fluid-structure Interaction

Hydrodynamic pressure type mechanical seals have the advantages of good lubrication performance,small temperature rise and long service life.However,for the micron-sized sealing gap,the slight deformation of the sealing end face may cause significant changes in the lubricating film and sealing performance.It can also cause deterioration of the lubrication state or even seal failure.Therefore,based on the study of the influence of dynamic pressure liquid mechanical seal structure parameters on the deformation and sealing performance of the seal face,the multi-objective optimization algorithm is used to optimize the sealing performance.The specific research work and conclusions are as follows:1.The fluid-solid coupling calculation model suitable for dynamic pressure liquid mechanical seal is established,and the correctness of the fluid-solid coupling calculation model is verified.2.The numerical simulation analysis of the fluid-solid coupling of the seal ring and the liquid film is carried out by using the established calculation model.The influences of structural parameters such as load factor,thickness-to-diameter ratio,spring placement diameter and spring specific pressure on the deformation of the end face and the sealing performance were obtained.The research shows that the sealing performance parameter value is larger than the calculation result of fluid-solid coupling due to the deformation of the end face considering the fluid-solid coupling effect;the deformation and stress value of the static and dynamic ring end face decrease with the increase of the load factor and the aspect ratio.As the spring placement diameter and the spring specific pressure increase,the area of the seal end face deformation and stress is located in the spiral groove area;the sealing performance parameter value decreases with the increase of the thickness-to-diameter ratio,and is placed with the spring.The diameter and spring specific pressure increase,but the load coefficient shows a significant nonlinear relationship.The analysis shows that the thickness-to-diameter ratio has the greatest influence on the sealing performance,and the load factor has a complicated influence on the sealing performance parameters.And the impact is relatively large.3.According to the research results of the influence of structural parameters on deformation and sealing performance and the related research results of the influence of theend face micro-molding parameters on the sealing performance,the load factor,the aspect ratio,the groove depth and the helix angle are determined as the optimization variables to the leakage amount and the liquid film stiffness.In order to optimize the target,the fitting equation between the optimization variable and the optimization target was established by multiple regression analysis,and the influence of the interaction relationship between the optimization variables on the sealing performance was analyzed.4.A multi-objective optimization research method considering dynamic fluid-type mechanical seal based on fluid-structure coupling is established.Through the uniform test design method and using the DPS data statistics system,50 sets of sample points were obtained,and the workbench platform was used to carry out numerical simulation calculation and establish a database.According to the neural network topology,the parameters of the physical layer in the neural network are reasonably set.The BP neural network is established and the fitting function between the optimized variable and the optimized target is obtained.The multi-objective optimization is obtained by using the MATLAB optimization toolbox to obtain Pareto.Frontier solution set.The two sets of optimization schemes were selected from the Pareto solution to carry out numerical simulation calculation and compared with the original model.The results show that the liquid film stiffness of the two optimization schemes is 8% and 12.6% higher than the original model,respectively,and the leakage is lower than the original model.10%,11.6%,and the experimental results were verified.