双脉冲发动机点火过程三维数值模拟

以喷射棒式双脉冲发动机燃烧室、级间隔离装置和喷管一体化为研究对象,采用数值仿真技术对Ⅱ脉冲点火过程三维流场特性进行分析研究。计算结果表明,点火初期燃气压力波峰超前于火焰峰到达级间隔离装置,并以压强冲击波形式传播,Ⅱ脉冲燃烧室相对高压区位置不断发生改变;级间孔打开过程对药柱末端压强影响较大,但对Ⅱ脉冲燃烧室压强整体上升过程影响较小;级间孔打开后,燃气经级间孔加速后形成高度欠膨胀射流,并在Ⅰ脉冲燃烧室内形成非对称带状低压区;级间孔分布的非对称性,导致压强及温度在发动机燃烧室中呈现显著的三维分布特性;高温区出现在隔板附近,而在装药前端、装药末端及外围级间孔轴线附近出现低温区。

Three-dimensional ( 3D) numerical simulation for the ignition process of a dual-pulse motor

Taking the chamber, pulse separation device ( PSD) and the nozzle of dual pulse motor as research objectives, the three dimensional ( 3D) flow field characteristics of fuel gas were studied and analyzed during the ignition process of the second pulse chamber by means of numerical simulations. The results showed that at the beginning of ignition, the ignition gas pressure wave arrived at the PSD prior to the flame and spread in the form of pressure shock. The position of the high pressure zone was con-stantly changed with time. The opening of interstage hole had a greater effect on pressure at the end of the propellant, but less effect on the whole process of pressure increasing in the second chamber. A highly under-expanded jet and a non-symmetric band high-speed expansion zone were formed in the first chamber after the gas-flow through the interstage hole. The pressure and temperature contours were found to be significant 3D flow field paramters in the chamber because of the asymmetry distribution of the PSD. The higher temperature zone was located in the front cavity of clapboard, but the lower temperature zone was located in the rear end of the propellant charge, as well as the axial neighborhood region of the interstage hole.