运载火箭贮箱增压消能器流场数值仿真方法研究

在液体运载火箭贮箱的入口,通常采用增压消能器对贮箱增压气体进行均流、减速,使增压气体平稳、缓慢地降落在推进剂液面上。增压消能器通常由多层筛网、导流锥、扩容腔等部件组成。根据美国NASA的半人马座火箭采用的喇叭口消能器结构和参数,使用计算流体力学(CFD)方法对该种喇叭口形消能器的稳态工作过程进行了数值仿真,获得了消能器工作时的内部流场。通过与美国Lewis中心的消能器试验数据对比,发现仿真结果与试验结果吻合,验证了仿真方法的正确性。研究表明:消能器内部的一级筛网是产生能量损耗的主要来源,设置容腔及增大流通面积能有效降低气体的流动速度,多层筛网对均匀气体分布起到很好的效果。本文应用的流场仿真方法可以推广至其他类型的消能器,为增压消能器的选型、优化设计起到参考作用。

Research on Numerical Simulation Method of Diffusers in Launch Vehicle Tanks

At inlets of liquid launch vehicles'' tanks, diffusers are used to reduce the velocity and improve uniformity of the pressurized gas, aiming to make pressurization smooth and steady. Diffusers are composed of screens, diversion cones and large cavities. Based on the structure and parameters of the diffuser of NASA''s Centaur rocket, this research used Computational Fluid Dynamics(CFD) and completed the numerical simulation of its steady working process, and thus, the internal flow field was explored. Good agreements were observed between the current numerical simulation and experimental data according to the literature of Lewis Center, which explained that the numerical simulation method was correct. The research revealed that the first screen was the main source of energy loss, setting the cavity and increasing the flow area could effectively reduce the pressurized gas velocity, and the multi-layer screen played a good job in making the gas uniform. The numerical simulation method can be applied to other kinds of diffusers, and the results can be potentially used for model selection, design and optimization of diffusers.