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

摘要： 为了研究内部流场对减压器动态特性的影响，基于新离散几何守恒律和高精度界面流固耦合技术对其动态特性进行数值模拟，其中单自由度质量弹簧阻尼结构动力学模型采用Newmark法进行计算；三维非定常积分形式的ALE流体控制方程采用弹簧近似的动网格有限体积法进行求解。采用虚拟网格通气技术实现阀门内部运动部件接触/分离过程引起的计算区域拓扑变化。计算结果表明，在减压器正常工作状态下，出口压力存在振荡现象，其均值接近按照静态性能设计的理论值；进口压力增高，振幅减小；进口压力太低时，减压器无法实现出口压力的设计理论值。在正常工作状态的进口压力范围内，减压器存在颤振现象，出口压力远大于设计理论值。

关键词: 流固耦合；非结构动网格；颤振；动态特性