Dynamic Analysis Of Dry Gas Seal T-Groove And Optimization Design Of Groove Bottom Microtexture

Dry gas seal as a non-contact seal combines fluid lubrication theory and fluid mechanics knowledge on the basis of mechanical seal.Because of its low loss and small leakage,it is widely used in various rotating machinery and equipment with sealing requirements(compressor,reactor,turbine machinery,etc.).Compared with the traditional one-way groove structure,there is insufficient reverse rotation opening force;During the startup and shutdown stages,problems such as abrasion damage are easy to occur,and the two-way rotating non-contact seal has more stable operation performance.At present,the two-way rotary dry gas seal is developing towards high parameters as a whole,so it is more necessary to understand its dynamics in detail in order to obtain the best performance.This article takes the representative T-shaped groove of bidirectional rotary dry gas seal as the research object,and studies and calculates the sealing performance parameters of the T-shaped groove of bidirectional rotary dry gas seal to obtain its dynamic changes under general working conditions;Secondly,in order to improve the dynamic pressure effect,the T-groove micro-texture coupling structure is introduced into the design of the seal face,and the geometric parameters of the coupling structure are optimized to optimize its sealing parameters.The main content and conclusions of this paper are as follows:Firstly,the flow pattern and continuity of the gas film in the sealing gap is judged,the finite difference method is adopted,and the central difference format is selected to discretize the Reynolds equation.The corresponding calculation boundary conditions and convergence conditions are set,and the specific expression and numerical calculation flow chart for calculating the sealing performance parameters are given.And then on the basis of satisfying the axial force balance,the ultra-relaxation iterative method is used to solve the relevant characteristic parameters of the cover.As a result,the thickness and pressure distribution of the lubricating oil film is obtained.The numerical calculation of the micro-gap flow field in the T-groove of the dry gas seal is carried out,the opening force,leakage rate,and floating leakage ratio were used as evaluation indicators to explore the impact of changes in working conditions and structural parameters on sealing performance.The general flow field analysis results of the structural parameters and working conditions of the T-shaped groove of dry gas seals and the evaluation indicators were obtained.After that,referring to the literature with relevant test content,considering that the theoretical calculation under real operating conditions is within the error range(the maximum difference point difference is not more than 8%),the rationality and correctness of the program calculation in this article have been proved.In addition,let the dynamic pressure effect performance better,on the basis of ensuring the stable operation of the sealing equipment,considering the introduction of ordered micro texture design based on the idea of creating micro textures,it is expected to obtain the better dynamic pressure effect.Calculate the sealing performance parameters of several micro-texture coupling groove types under different working conditions,and compare the steady-state characteristic parameters with the dry gas seal T-shaped groove under the same working conditions.After comparing the non-micro-texture groove,it is proved that the ordered micro-texture design is feasible to improve the dynamic pressure effect.Next,compare the micro-texture layout mode(horizontal and vertical,density,length and width)for analysis,The results show that the T-shaped groove with micro-texture design has better dynamic pressure effect and stability,and the micro-texture design has the best design interval.Finally,in order to improve optimization efficiency,the optimization algorithm was compared and applied to the micro texture design of dry gas seal T-shaped grooves using particle swarm optimization.An appropriate formula was selected to calculate and verify its convergence and reliability,and was substituted into the sealing parameter calculation to obtain the optimal groove parameter range of the micro texture.After verification,the feasibility of the algorithm’s optimization application was proved,and the pressure field before and after optimization was displayed to indirectly prove the rationality and correctness of the optimization algorithm.The research in this topic has certain theoretical and reference significance for the calculation and analysis of bidirectional rotary dry gas seals,and can also provide certain ideas and theoretical and technical support for the follow-up dynamic research and ordered micro texture design of bidirectional rotary dry gas seals.