DFHF化学激光器喷管流动数值模拟结果

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

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。

Two dimensional flow fields in different nozzles with equal section throat area and different section length were simulated. The change of sonic line with the section length was described, while the optimum length of the section were given. The flow fields and the performance of three nozzles designed with different methods were simulated and analyzed. Results of simulation show that the new method can optimize and promote the performance of nozzle, such as lateral velocity, 'freezing' efficiency of fluorine atom and longitudinal velocity, and also can prevent boundary layer separation and shock wave. The thickness of boundary layer is calculated according to the velocity field obtained from simulation. Developing tendency of boundary layer in the nozzle of DF/HF chemical laser was discussed.