COIL亚声速段横向喷流混合流场数值分析

 COIL是一个气体动力学、化学反应动力学以及光学相互耦合的复杂过程。作为高总压COIL系统研究的第一步,利用三维CFD技术对传统的COIL亚声速段横向射流混合过程进行了数值分析,讨论了包括压力梯度驱动项的分子扩散机制,得到了横向射流的较精细的结构,如马蹄形射流界面、逆旋涡对以及射流剪切层。结果表明,压力梯度驱动项对重、轻组分的扩散作用相反,重组分沿压力梯度正向扩散,轻组分逆压力梯度方向扩散。在射流穿透不足的情况下,仍然在喷管出口得到了约为0.01 cm^-1的小信号增益系数。

Numerical simulation on the flow field of COIL mixing nozzle with injection from subsonic region

Three-dimensional CFD technology was used to simulate the flow field of COIL mixing nozzle. Concentration-driven as well as pressure-driven diffusion terms were considered in the diffusion equations. The 10 species and 21 reactions chemical model was applied to implement the chemical kinetics. Some elementary fluid dynamic phenomena of a round transverse jet were obtained such as the horse-shoe-shaped jet trajectory and the counter-rotating vortex pairs. The results indicate that the pressure-driven diffusion term has contrary effects on species of different molar weight, the molecular of "heavier" species diffuses toward the pressure gradients and that of "lighter" species against the pressure gradients. It was also found that even complete jet penetration was not achieved, the gain field of 0.01 cm~(-1)was obtained near the outlet of the mixing nozzle.