固体火箭发动机喷管壁窜火故障的试验研究

针对某大型固体火箭发动机在试车中后期出现的喷管后侧持续冒小火和试车后期出现的喷管扩散段前部窜火故障，进行了模拟试验。结果表明：如果在喷管扩散段的中、后部壁上有侧孔（此孔无论是烧穿形成，或其他原因形成），并在侧孔处有阻挡气流的物件，使该处的气流局部滞止，即能造成喷管后部侧孔窜火。发动机喷管经常出现的扩散段前段窜火，则是由于喉面下游壁厚烧薄到一定程度，当地的静压就能使火苗窜出。

EXPERIMEANTAL INVESTIGATION ON FLAME-LEAK OF NOZZLE IN SOLID ROCKET MOTOR

According to the fault in ground tests of flame-leak of nozzle of a large solid rocket motor, a series of simulation tests cheking the fault has been carried out. Firstly, small flame-leak taking place at the rear side wall of the nozzle in middle period of testing has been checked by simulation tests. The test results demonstrate that if there are side holes in the middle and rear side wall of divergent section of nozzle, flame-leak can not happen by the effect of local static pressure only. However if there are any resistant part in gas flow against the hole, making the local gas flow partly stagnated, the flame-leak takes place at this hole affirmly although the local static pressure is very low. Besides the simulation tests, analytical calculations have been made in accordance with the principle of flame-leak.Other simulation tests have been made in order to check the flame-lake taking place several times in the forehead of divergent section of prototype nozzle. The tests demonstrated that if there is any hole punched by burning erosion at the forehead of divergent section of the nozzle, the flame scurries off from the hole by effect of local static pressure only, so long as the local wall of nozzle is not thickenough.