Study on Factors Affecting Seal Performance of a Hydrostatic Mechanical Seal in Reactor Coolant Pumps

Abstract

A hydrostatic mechanical seal(HS-MS) for an nuclear reactor coolant pump(RCP) is studied.Marc finite element software developed by MSC Software Corporation is used to solve the whole non-linear two-dimensional axisymmetrical equations of the rotator by taking account of the influence of secondary seals on seal performance.The reasonable simplified boundary conditions for the rotator is presented.Based on this,a multiphysics coupled mathematic model for such a hydrostatic mechanical seal is established by considering the effect of temperature and pressure on viscosity of the sealed medium.Finite difference method is used to obtain the coupled solution of the Reynolds equation,energy equation,and thermal conduction equation,while finite element method is applied to compute the mechanical and thermal deformation of the end face.The effect of a bolt preload and the O-ring position on seal performance is comprehensively analyzed.The results show that a simplified model of seal ring with reasonable constrained boundary is vital for analyzing and designing a hydrostatic mechanical seal.Bolt preload of clamp and O-ring position have an apparent effect on seal performance.The bolt preload increases lead to an increased opening force and an increased leakage rate.When the position of O-ring is located on the outside of the rotator,the seal stability descend.