基于流固耦合理论的关机水击特性

Characteristics of water hammer in shutting based on FSI

为了考虑结构变形对关机水击特性的影响,应用Workbench15.0构建双向流固耦合分析系统,模拟关机水击过程,通过压力和流线的分布图分析压力波传播和能量耗散。根据轨控发动机大流量、高室压、快响应的发展趋势,设计了8个工况来分析流量、压力、阀门关闭时间对水击特性的影响。仿真结果表明:在水击发生后,水击的能量只有小部分通过从入口流出和结构变形而耗散,大部分水击能量的耗散是由于流体的粘性损失。流量只对水击峰值压力有影响,且流量越大,水击峰值压力越大。阀门关闭时间的缩短增加了峰值压力和水击频率,减缓了衰减速率。管路背压对水击特性几乎没有影响。因此,在进行轨控发动机高室压水击试验时,在保证流量和关阀时间相同的情况下,减小出口背压,可以得出与高背压一致的水击压力变化曲线。

In order to consider the effect of structural deformation on water hammer characteristics, two-way FSI analysis system was built to simulate water hammer.The propagation of pressure wave and energy dissipation were analyzed through pressure and streamline distribution.According to the development trend of orbit-control engine, eight working conditions were designed to analyze the effect of backpressure, flux and valve closing time on water hammer characteristics.The simulation results indicate that, only a small part of the energy of water hammer is dissipated through flowing out from the inlet and the structural deformation, and most of the energy dissipation is due to the viscous loss of the fluid.The flux only affects the peak pressure of water hammer.The greater the flux is, the larger the peak pressure of water hammer is.The shortening of valve closing time increases peak pressure and frequency of oscillation, and reduces the attenuation rate.Backpressure has no effect on water hammer characteristics.Therefore, in the high-pressure water hammer test of orbit-controlled engine, the outlet back-pressure can be reduced under the same flux and valve closing time, and the water hammer pressure curve consistent with that under high backpressure can be obtained.