A Coupling Static-dynamic Mechanical Seal Model With Considering The Gas-liquid Phase Flow Conditions

Liquid rocket engine high speed turbine shaft end mechanical seal(also known as the end face seal),is an important function of the pump system components,to prevent the engine fuel and oxidant leakage contact.For this reason,the scheme of the combination of dynamic and static mechanical seal is put forward.The theoretical and experimental results show that the system has the advantages of reliable operation,low leakage,low power consumption,long service life and automatic compensation of the end face wear.However,due to such work in a low temperature environment is extremely high seal,there will be serious two-phase flow.Therefore,it is very necessary to model to consider the factors of lubrication model of two-phase liquid lubricated mechanical seal based on the existing pure.In this paper,a homogeneous gas-liquid two-phase flow lubrication model with static and dynamic mechanical seals is proposed and a numerical solution to its related characteristics is carried out,which provides a theoretical basis for the high reliability and stability of the seal.The specific contents of the thesis include:Firstly,the coupling model of the static and dynamic combined mechanical seal is established by coupling the two-phase flow density viscosity model.The model can be used to explain the mechanical coupling fluid mixing sealing film forming mechanism.The dimensionless model including the generalized Reynolds equation,state equation and two-phase flow model.Finite element method is used to solve the coupling model.The pressure distribution,leakage,seal opening force(closed),power consumption,temperature rise and typical the dynamic coefficients(8 stiffness and damping coefficient)is obtained.Secondly,the calculation results are analyzed.The mechanical seal performance is obtained by the 5 aspects of load,leakage,power dissipation,stiffness and damping coefficient in the article.Thirdly,the parameter optimization of the spiral groove mechanical seal is designed.The design parameters is the groove depth,the slot number and the spiral angle of the seal.The goal of optimization is selected as the largest K/Q(the stiffness coefficient / the seal leakage),low power consumption of liquid film.The results of the parameter optimization design show that the slot number is 10,the groove depth is 0.005 mm and the spiral angle is 17.5 degrees.Finally,the spiral groove mechanical seal is tested.The test system consists of a transmission system,sealing system and data acquisition system.The experiments show that,the temperature gradually increased with the increase of speed and the emergence of the phenomenon of two phase flow appeared when the speed reached a certain level.The results of this study can be used to guide the design of the mechanical seal of the shaft end of the high speed turbine under extreme conditions.The study can also provide the reference for other types of two-phase flow under the lubrication seal and bearing design.