V形尾缘喷管流场与红外特性的数值模拟

Numerical simulation on flow field and infrared characteristics of chevron nozzles

采用有限体积QUICK格式和重整化群(RNG)k-ε湍流模型,并结合壁面函数,同时利用离散坐标法DOM(Discrete Ordinates Method)计算热辐射,以灰气体加权模型WS-GGM(Weighted-Sum-of-Gray-Gases Model)确定气体介质的辐射性质,求解N-S方程、固壁中的热传导方程、考虑吸收-发射性气体介质的辐射传输方程.采用此耦合计算模型对V形尾缘的收敛喷管进行了数值模拟,计算所得数据与试验吻合良好.在此基础上,对有/无V形尾缘收-扩喷管的内外流场与红外特性开展了数值模拟.结果表明:V形尾缘在尾喷流的剪切层中产生了强烈的流向涡,促进了内外流的强化混合,明显缩减了喷管出口附近喷流的红外辐射.

The QUICK and finite volume method, RNG k-ε turbulence model, wall functions, discrete ordinates method （DOM） and the weighted-sum-of-gray-gases model （WSGGM） were employed to solve N-S equation, thermal conduction equation in solid wall and radiation transfer equation. A converging nozzle with chevron trailing edge was simulated, and the computed results were validated with available experimental data. The internal and external flow field and infrared characteristics of a converging-diverging nozzle with or without chevron trailing edge were simulated. The result of this research shows that the chevrons induce streamwise vortices into the shear layer, which lead to increased mixing and is benefit to the reduction of infrared radiation of the plume especially near to the nozzle exit.