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为研究双脉冲固体火箭发动机Ⅱ脉冲点火瞬态过程,发展一套多物理场耦合求解器。流体控制方程基于有限体积法求解,时间推进采用双时间步LU-SGS(Lower Upper Symmetric Guass Seidel)方法;固体推进剂表面温度基于耦合传热方法计算;结构动力学运动方程基于有限元方法离散,采用经典的Newmark格式进行时间推进,流固耦合采用松耦合算法,并通过算例验证求解器的可靠性。计算结果表明:该求解器能够数值模拟Ⅱ脉冲启动过程中的点火药气体冲击、燃气非定常流动及金属膜片机械响应过程,获得金属膜片的破裂时间和压强;且随着点火质量流率增加,推进剂装药首次点燃时间和金属膜片破裂时间变短,膜片破裂压强降低;金属膜片破裂时间和压强不仅与作用在其表面的压强载荷大小相关,而且与压强载荷加载的过程相关;金属膜片厚度越薄,膜片破裂时间越短,膜片轴向位移越大,膜片破裂压强越低。
To study the transient process of pulse ignition of a two-pulse solid propellant rocket engine II, a multi-physics coupled solver is developed. The fluid control equations are solved based on the finite volume method. The time advance is based on the LU-SGS (Lower Upper Symmetric Guass Seidel) method. The surface temperature of the solid propellant is calculated based on the coupled heat transfer method. The structural dynamics equations are discretized based on the finite element method. The classic Newmark format was used for time advancement. The fluid-structure interaction was loosely coupled and the reliability of the solver was verified by an example. The results show that the solver can simulate the ignition of gas propellant gas, unsteady flow of gas and the mechanical response of metal diaphragm during the start-up of Ⅱ pulse, and obtain the rupture time and pressure of metal diaphragm. With the increase of ignition mass flow rate The ignition time of the propellant charge and the rupture time of the metal diaphragm become shorter and the rupture pressure of the diaphragm decreases; the rupture time and pressure of the metal diaphragm are not only related to the pressure load acting on the surface, but also to the process of the pressure load loading Related; the thinner the thickness of the metal diaphragm, the shorter the diaphragm rupture time, the greater the axial displacement of the diaphragm, the lower the rupture pressure of the diaphragm.