基于有限差分WENO格式的推进剂供应管路充填特性研究

Priming Behaviors in Propellant Feedline Analysis Based

关键词:  充填过程  高阶有限差分方法  频率相关摩擦  数值模拟

Key words:  Priming process  High order finite different method  Frequency-dependent friction  Numerical simulation

摘要:

推进剂供应系统的充填特性对发动机起动过程控制具有重要意义，而供应系统管路系统复杂，需要具有边界协调性好、计算精度高、稳定性好的WENO格式。为了模拟充填过程液体压力的瞬变特性，将流动控制方程进行坐标变换解决移动边界的问题。针对坐标变换后的流体瞬变流动控制方程，获得带源项的双曲方程组，利用基于特征变量的Roe类型高阶有限差分WENO格式建立了适用于推进剂充填过程的一维瞬变流动仿真模型。考虑稳态摩擦的情况下，对带气垫的推进剂充填过程利用WENO格式和显式特征线法进行了仿真，结果表明WENO方法的耗散小、预测结果更好。考虑了介质物性、摩擦系数、频率相关摩擦、多变过程指数等对充填过程的影响，研究结果表明瞬态摩擦模型和多变过程指数对水击压力的峰值和衰减过程有显著的影响。

Abstract:

Priming behaviors in propellant feed system are crucial for the control of start-up of engine. However，due to the complexity of the feedline network，it is natural to choose weighted essentially non-oscillatory (WENO) schemes in terms of boundary coordination，numerical accuracy and stability. In order to capture the transients of filling process and deal with the moving boundary，the one-dimensional transient flow governing equations are transformed and rewritten to get hyperbolic governing equations with source terms，so that the high order finite different Roe-type WENO scheme based on characteristic elements is applied to solve the new one-dimensional transient flow hyperbolic governing equations with source term. Based on steady friction model，WENO schemes and explicit method of characteristic (MOC) are carried out to calculate the transients of priming process in a simple purging system with purged gas. Thereafter，the solution of WENO are demonstrated by compared with that of MOC，the results indicate WENO schemes produce better results with less dissipation. Moreover，the effects of friction model on transient behavior of priming process were obtained by WENO scheme，and frequency-dependent model has significant effect on the damping of the pressure. Besides，the effects of filling media，friction factor，frequency-dependant friction and polytropic exponent on priming behaviors were obtained，the results illustrate that friction model and polytropic exponent have obvious effect on the attenuation and the maximum pressure of water hammer pressure in the purging process.