液体火箭液氧贮箱增压与结构耦合分析

Pressurization-structure Coupling Analysis of Liquid Oxygen Tank of Liquid Rocket

一部分增压气体带入的能量通过与壁面热交换传递给贮箱壁面,传热过程快慢与增压气体流场和贮箱结构密切相关,而贮箱增压计算与结构设计分开进行,造成设计过程繁琐且周期较长,因此贮箱增压与结构耦合分析对于贮箱的设计具有重要意义。从现有文献来看,研究人员主要采用零维整体模型与一维分层模型分析增压过程,但以上两种模型仍存在不能展示箱内物理量的径向及局部分布等缺点,造成增压计算与结构耦合分析难以开展,计算流体力学技术将弥补这方面的不足。本文基于VOF(Volume of Fluid)方法建立了液氧贮箱的二维轴对称非稳态模型,对贮箱增压过程进行了数值模拟,固壁区的传热采用热阻试算法计算,通过与贮箱遥测数据进行比对,验证了模型的正确性。模型计算得到了气枕压力、和贮箱壁面温度的变化规律,并对壁面厚度和温度、增压气体温度和流量及其之间的作用规律进行了优化分析,结果显示增压气体温度、流量、壁面温度与厚度有强烈的耦合关系,结论可为贮箱结构设计提供理论依据。

View from the existing literature, zero-dimensional integrated model and one-dimensional stratification model were adopted to analyze the pressurization process. However, those models don’t provide any predictions of radial and local distribution for physical quantities. Then computational fluid dynamics (CFD) make up for the deficiencies of those models. In this paper, a two-dimensional axisymmetrical model based on VOF (volume of fluid) method was set up to solve the unsteady process of liquidoxygen tank. The model was used to simulate the tank pressurization process. The trial method of thermal resistance is adopted for heattransfer of the tank wall. The validity of model was tested through the comparison with the experimental data. The simulated resultsprovided the distributions of the gas pressure, gas temperature and wall temperature of tank. And the optimization analysis of wallthickness and temperature, pressurization gas temperature and rate of flow, and their working principle were conducted. The results show that, there is a strong coupling relationship among wall thickness, wall temperature and pressurization gas temperature and rate of flow. The conclusion provided the theoretical basis of tank structure design.