Abstract:Considering the influence of the pressure change of end face caused by the dynamic pressure groove,the phase change characteristics of the double spiral groove liquid film seals were discussed.A phase change model of liquid film seal was established based on the theory of homogeneous mixtures,the governing equations were discretized by finite volume method,and the influence of liquid film phase change on sealing performance and end face pressure distribution was analyzed.Results show that the viscosity is decreased obviously after phase change,which causes the lateral spiral groove squeezing effect and pumping capacity to weaken,in the coupling with phase change,the opening force is decreased first and then increased,the leakage is increased first and then decreased,the sealing performance is decreased compared with full liquid membrane.High pressure generated by the inner spiral groove suppresses the phase change,and there is no change in the pressure distribution.The region of phase change is larger in the outer spiral groove,the pressure distribution is changed obviously.