复杂服役环境下高压阀门疲劳可靠性数值分析

Numerical Analysis on Fatigue Reliability of High Pressure Valves in Complex Service Condition

高压阀门因长期处于高温、高压工况下,同时还需承受温度场、流场和压力场等多个物理场的耦合作用,故在使用较短的时间后就可能因产生裂纹、泄漏、疲劳破坏等而失效。为了提高高压阀的抗疲劳可靠性,基于疲劳累积损伤理论,运用名义应力法得到耦合作用下阀门的疲劳寿命,并借助于ANSYS仿真软件对其进行模拟,得到了阀门在高温高压环境下稳定工作的温度场和应力场的分布规律。仿真结果表明:阀门工作过程中,受到损伤最大的区域为其入口和出口靠近锥阀槽内的转角处,可采取对该部位进行热喷涂以减少结构突变、增大过渡圆角以使结构强度分布均匀、选择更合适的材料等措施进行改善,从而提高阀门的可靠性。

High-pressure valves may fail due to cracks, leakage and fatigue failure after a short period of time when they are under high temperature and high pressure conditions for a long time, where they also need to bear the coupling effects of temperature field, flow field and pressure field. In order to improve the fatigue reliability of highpressure valves, based on the fatigue cumulative damage theory, the fatigue life of valves under coupling action can be obtained by using the nominal stress method. Moreover, the simulation by ANSYS simulation software helps to work out the distribution law of temperature field and stress field of valves working steadily under high temperature and high pressure. The simulation results show that the most likely damaged area is the corner of the entrance and exit of the valves near the cone groove, which can be improved by thermal spraying to reduce the structural mutation, increase the transition fillet to make the structural strength distribution uniform, and select more suitable materials so as to improve the reliability of the valves.