Experimental investigation on small-scale model of gas channel in directly drained CW DF/HF chemical lasers

To study the starting characteristic of directly drained CW DF/HF chemical lasers(DDCL), a single-nozzle small-scale model of DDCL gas channel was set up, and a series of experiments were conducted with different working mediums and several diffusers. The effect of gas dynamic parameters of medium on the starting characteristic and minimum area of diffuser throat was also studied. The experimental results are compared with those caculated by one-dimension Steady State Theory. In addition, the effect of the base of the nozzle on the starting characteristic is discussed, and the comparison between two types of bases is made. The result indicates that the most effective means for improving the performance of DDCL is to operate with high specific heat ratio, low molecular weight primary gas an