DFHF化学激光器喷管流动数值模拟结果

模拟得到了喉部具有不同等截面段长度的二维喷管流场 ,指出了音速线随该长度的变化规律和等截面段最佳长度。模拟分析了三种不同方法设计的喷管流场和性能参数 ,结果表明新方法设计的喷管具有合适的横向速度 ,提高了喷管对F原子“冻结”效率、纵向速度等性能参数 ;能防止喷管内边界层分离和激波产生。并根据数值模拟得到的速度分布型计算了边界层位移厚度 ,讨论了DF HF激光器上述三种喷管内边界层发展规律。

Numerical Simulating Results of Nozzle Flow in DF/HF Chemical Lasers

Two dimensional flowfields in different nozzles, with equal section throat area and different section lengthhave been simulated. The change of sonic line with the section length, and optimum lengthof the section have been given. The flow fields and the performance of three nozzlesdesigned with different methods, have been simulated and analysed. Results of simulationshow that the new method can optimize/promote the performance of nozzle, such as lateralvelocity, the efficiency of “freezing” fluorine atom and longitudinal velocity, and also can preventboundary layer separation and shock wave. Moreover, thickness of boundary layer has beencalculated according to the velocity field obtained from simulation. Developing tendencyof boundary layer in the nozzle of DF/HF chemical laser has been discussed.