固液捆绑火箭起飞喷流特性及对发射台影响研究

Study on the Takeoff Jet Characteristics of Solid-Liquid Bundled Rocket and Their Effects on the Launch Pad

为了研究固液捆绑火箭起飞阶段多簇高度欠膨胀燃气射流冲击发射台及导流装置的复杂流场图谱,基于连续介质假设,建立固液捆绑火箭发射燃气羽流含Al2O3颗粒混合物流动的欧拉离散相气-固耦合流动模型,包括燃气多组分可压缩N-S方程、Al2O3颗粒流动方程、RNG k-ε湍流模型,并运用二阶Roe迎风差分格式求解控制方程的对流通量,二阶中心差分计算耗散项。在流动计算结果基础上,建立高温燃气射流的热辐射方程,采用离散坐标法(DOM)计算多簇燃气射流热辐射的影响,通过数值模拟得到火箭起飞时高度和漂移量对发射台和箭体底部底部燃气射流流动及热流密度的影响。所得结果可为发射台和箭体底部防热设计提供一定的参考依据。为了验证欧拉离散相模型及其数值方法的有效性,以固体推进剂标准发动机羽流热环境实验为对象,将数值模拟结果与实验数据进行了对比,发现两者的温度和热流密度相对误差分别为2.2%和3.7%,由此可见本文的方法具有良好的数值精度。

Based on the continuum assumption,an Euler discrete phase gas-solid coupling model for the flow of Al2O3particle mixture in the gas plume generated by solid-liquid bundled rocket is established. In the model,the multi-component compressible Navier-Stokes(N-S) equation, the Al2O3particle flow equation, and the renormalization group(RNG)k-ε turbulence model are considered,the second-order Roe upwind difference scheme is used to solve the convective flux of the control equation,and the second-order central difference is used to calculate the dissipation term. The complex flow field map is obtained,showing multi-clusters of highly underexpanded gas jets impacting the launch pad and guide device during the take-off stage of solid-liquid bundled rocket.Based on the calculation results,the thermal radiation equation of high-temperature gas jet is established,and the influence of multi-cluster gas jet thermal radiation is calculated by the discrete coordinate method(DOM). Through large-scale numerical simulation,the correlations of rocket height and drift on the flow and heat flux at the launch pad and the bottom of the rocket body are obtained. The prediction results provide some references for the thermal protection design of the launch pad and the bottom of the rocket body. In order to verify the effectiveness of the Euler discrete phase model and its numerical implementation,the numerical results are compared with the experimental data for the plume thermal environment experiments of solid propellant standard engine. The relative errors of temperature and heat flux are 2.2% and 3.7%,respectively,indicating that the method of this paper has good numerical accuracy.