A Comparative Study of SPH and Eulerian Methods for Space Reactor Water Impact

随着我国航空技术的发展，深空探测、星表基地等任务需求逐渐进入视野，空间堆的重要性愈发显著。而空间堆发射跌落撞击地表问题是空间堆安全设计的核心内容，当空间堆高速撞击水体时，极高的速度与巨大的冲击力使得堆本体与自由液面发生剧烈变形，极大增加了流固耦合的复杂性，使得基于传统拉格朗日网格的有限元方法难以得到正确解答。本文通过建立空间堆整体几何模型，定义适用于高速撞击时的材料本构模型和状态方程模型，基于光滑粒子流体动力学(SPH法)以及欧拉法进行空间堆撞击水体有限元仿真分析，具体对反应堆以200 m/s、50 m/s等速度以及正面、45˚、侧面等角度撞击水体进行模拟计算，对比了两种方法的计算结果及计算效率，得到了可信的结构破坏结果与危险工况分析。本文高速撞击水体的有限元模拟方法可为相关研究提供有益的参考，结构破坏结果可为空间堆发射跌落事故安全分析提供重要依据。With the advancement of aerospace technology in China, mission requirements such as deep space exploration and extraterrestrial surface bases have gradually come into focus, highlighting the significance of space nuclear reactors. The issue of space reactor impact upon launch failure and subsequent collision with the Earth’s surface is a critical aspect of space reactor safety design. When a space reactor impacts a body of water at high velocity, the extreme speed and substantial impact force cause severe deformation of both the reactor structure and the free liquid surface, significantly increasing the complexity of fluid-structure interaction. This complexity renders traditional Lagrangian mesh-based finite element methods inadequate for obtaining accurate solutions. This study constructs a comprehensive geometric model of the space reactor, defines material constitutive models and equations of state suitable for high-velocity impact scenarios, and conducts finite element simulation analysis of the reactor’s impact on water using both the Smoothed Particle Hydrodynamics (SPH) method and the Eulerian method. Specifically, simulations are performed for reactor impacts at velocities of 200 m/s, 50 m/s, and at angles of 0˚ (head-on), 45˚, and 90˚ (side-on). The computational results and efficiency of the two methods are compared, yielding credible structural failure outcomes and hazardous scenario analyses. The finite element simulation methodology for high-velocity water impact presented in this study provides valuable references for related research, and the structural failure results offer important insights for the safety analysis of space reactor launch failure accidents.