| Dry gas seal(DGS)has become the preferred type of shaft surface seal for high-speed rotating machinery because it can realize the non-contact operation of seal dynamic and static rings and strictly control the leakage energy of sealing medium.It is widely used in petrochemical industry,energy,electricity,food,medicine and other fields.By optimizing the sealing surface structure,the bearing capacity and the stiffness of the fluid film can be improved remarkably,and the operation stability of the sealing surface structure can be improved.Therefore,it is of great significance to develop an optimum design software for dry gas seal surface groove with strong optimization ability and high design efficiency,in order to improve the design efficiency of dry gas seal surface groove and reduce the dependence on designers,and to improve the performance index and design level of existing dry gas seal in China.Firstly,based on the theory of gas lubrication,the Reynolds equation is solved by finite difference method,and the steady-state performance parameter calculation model of dry gas seal is established.The correctness of the model is verified by comparing the literature.In order to obtain the geometric parameters of the surface structure with better sealing performance,the principle and flow chart of three typical geometric parameters optimization methods,namely,single factor optimization method,cyclic iteration optimization method and genetic algorithm,are given.Secondly,aiming at the problems of numerous models and weak characterization ability of existing geometric models of dry gas seal face structure,generalized geometric models of dry gas seal surface structure with single and two-way rotating grooves are proposed respectively.The influence of working conditions and key geometric parameters on the steady-state sealing performance of classical dry gas seals with single and two-way rotating grooves is numerically analyzed,and the optimal geometric parameters of classical surfacestructures under different working conditions are obtained.On this basis,the effects of optimization objectives,working conditions and optimization methods on the steady-state performance of dry gas seals with single and two-way rotating grooves of different structures were analyzed comprehensively.The results show that the optimum geometric parameters of single and bidirectional rotating grooves of dry gas seals strongly depend on the operating conditions,objective functions and other geometric parameters.Compared with the opening force and film stiffness of classical end grooves obtained by single factor optimization,the structural model with stronger geometric characterization ability is adopted and the overall situation is stronger.The steady state sealing performance of the optimization algorithm is significantly improved.Finally,the software of optimum calculation of dry gas seal surface groove selection is developed by C++ QT framework,which integrates several classical groove models and optimization methods mentioned above,facilitates the extraction of design parameters and calculation results,achieves the functions of sealing performance calculation,groove structure optimization and display,and the optimization design efficiency of dry gas seal face groove is significantly improved. |
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