关键词: 流固耦合；非结构动网格；颤振；动态特性

Abstract: In order to investigate the effects of internal flow field on the dynamic characteristics of a pressure relief valve，based on the new discrete geometric conservation law and high order of fluid and solid coupling algorithm，numerical simulations of the dynamic characteristics were performed. The structure dynamic model of the single degree of freedom mass spring damping system was solved by Newmark method. The three-dimensional unsteady integral forms of ALE equation were solved by finite volume scheme based on spring analogy method and dynamic grid. The virtual mesh ventilation method is adopted to solve the problem when multiple bodies move from contact to separation and the mesh topology changes. The results show that the mean outlet pressure，which is consistent with the theoretical value of static performance design，appears oscillation under normal working state of the pressure relief valve，the higher inlet pressure，the lower amplitude. When the inlet pressure is too low the valve is unable to realize the theoretical value. Under the normal working state of the inlet pressure，the pressure relief valve may induce flutter and the outlet pressure is greater than the theoretical value.

Key words: Fluid and solid coupling；Dynamic unstructured grid；Flutter；Dynamic characteristics