基于Ansys-Workbench EPKM点火过程流固耦合仿真分析

Simulation analysis of fluid-structure interaction in EPKM ignition process based on Ansys-Workbench

利用Ansys-Workbench,通过对其Fluent流体计算模块进行编程嵌入,加入温度和压强点火判据来控制药柱内表面燃气的生成和燃面的扩展,并通过其Mechanical APDL(ANSYS Parametric Design Language)固体计算模块,以EPKM(LM-2E Perigee Kick Motor)型固体火箭发动机为算例,对点火过程中发动机内流场及结构场的变化情况进行了仿真分析。计算结果表明,点火燃气喷入燃烧室后形成的复杂的多个涡流会逐渐进行融合,在燃烧室管型药柱段及各个翼槽内各形成一个稳定且相对较大的涡流,直到喷管堵盖打开,该流动状态不再发生变化;翼槽内不论燃气的流动还是燃面的扩展,都是沿着翼槽前缘向着底部和后缘的方向;药柱在喷管堵盖打开前,尾部所受到的应力及其变形量大于头部,喷管堵盖打开后,头部翼槽侧面的变形量较大,药柱整个内表面受力比较均匀,沿径向逐渐降低,应变最大值满足药柱结构完整性要求。

Using Ansys-Workbench, by embedding the program to its Fluent module to add temperature and pressure ignition criteria to control the generation of gas and the expansion of the combustion surface on the inner surface of the grain, and by its Mechanical APDL(ANSYS Parametric Design Language) module, to simulate and analyze the changes of the internal flow field and structure field during the ignition process of EPKM(LM-2 E Perigee Kick Motor). The simulation results show that, the complex multiple vortices formed when the ignition gas is injected into the chamber will gradually merge into a stable, relatively large one at tube grain section and each wing slot, and it no longer changes until the nozzle plug is opened. Regardless of the flow of gas or the expansion of the combustion surface in the wing slot, it is along the front edge of the wing slot toward the bottom and the rear edge. Before the nozzle plug is opened, the stress and deformation on the tail of the grain is greater than that of the head. After the nozzle plug is opened, the deformation of the side of the wing slot is larger, the stress on the entire inner surface is relatively uniform and gradually decreases along the radial direction, and the maximum strain meets the structural integrity requirements of the solid propellant grain.