热喷干扰气体模型对飞行器气动特性影响分析

针对不同气体模型对高超声速飞行器喷流反作用控制系统(RCS)热喷干扰流场模拟的计算效率和准确性问题, 基于喷流燃气物理化学模型, 通过数值求解含化学反应源项的三维N-S方程, 建立了飞行器RCS热喷干扰流场数值模拟方法, 分别采用化学反应流、反应冻结流、二元异质流以及空气喷流四种气体模型开展了典型外形热喷干扰流场的数值模拟, 研究了不同气体模型对热喷干扰流场结构、飞行器气动力热特性的影响, 分析了不同马赫数、飞行高度下的变化规律. 研究表明: 化学反应流模型计算精度较高, 计算与风洞试验数据的吻合程度优于其他三种简化模型; 在本文的低空条件下, 采用简化模型进行热喷干扰流场数值模拟, 会低估分离区大小, 使飞行器气动力特性预测出现偏差, 同时也会低估表面热环境, 对防热系统设计不利, 随着马赫数增加, 简化模型对气动力热特性预估的误差进一步增大, 同时不同简化模型之间的差异也进一步增大; 飞行高度较高时, 模型之间的差异减小, 此时可采用简化模型进行计算以提高计算效率. 本文的研究结果可为飞行器热喷干扰流场数值模拟及喷流反作用控制系统设计提供参考. 

ANALYSIS OF GAS MODEL'S INFLUENCE ON AERODYNAMIC CHARACTERISTICS FOR HYPERSONIC VEHICLE OVER HOT JET INTERACTION FLOW FIELD

Gas model can have significant influence on the efficiency and accuracy of hypersonic vehicle’s reaction control system (RCS) hot jet interaction flow field simulation, the choice of gas model in numerical simulation is an important issue remains to be solved. Based on reaction jet hot gas’s physical and chemical reaction model and by solving three dimensional Navier-Stokes equation with chemical reaction source term, numerical simulation method of hypersonic vehicle’s reaction control system hot jet interaction flow field is established, by using chemical reacting flow, chemical frozen flow, binary gas model and simplified air jet model, numerical simulation of typical configuration’s hot jet interaction flow field is carried out, based on the simulation results, the influence of different gas model on hot jet interaction flow field structure and hypersonic vehicle’s aerodynamic characteristics is studied, the influences under various flight altitude and flight speeds are also discussed in detail. The result shows that: among the above four different gas models, chemical reacting flow model has higher precision, its result agrees better with wind tunnel experiment data than other three simplified models. In this paper’s low flight altitude conditions, using simplified model for hot jet interaction flow field simulation will underestimate the boundary layer separation length, which will introduce error to the prediction of vehicle’s aerodynamic characteristics, it will also underestimate the surface heat flux near nozzle exit, which is unfavorable for the design of thermal protection system. As the flight Mach number increases, the error introduced by simplified models increases, while the discrepancy between different simplified models also increases. In this paper’s high flight altitude conditions, the discrepancy between different gas models decrease, for these cases, simplified models are good to use for their high computation efficiency. These results can provide reference for future numerical simulation of hypersonic vehicle’s hot jet interaction flow field and the design of hypersonic vehicle’s reaction control system.