固体火箭发动机喷管烧穿故障的试验分析

THE ANALYSIS OF FAILURE OF NOZZLE BURNED-THROUGH IN SOLID ROCKET MOTOR TEST

关键词:  固体推进剂火箭发动机  喷管烧蚀  故障分析

Key words:  Solid propellant rocket engine  Nozzle ablation  Fault analysis

摘要:

根据某大型固体火箭发动机在地面试车喷管扩散段前部的烧穿故障的诊断，认为喷管的内型面半径对轴线的导函数在型面衔接点处不连续是导致烧穿故障的直接原因，通过对比模拟试验得到证实。又通过对原型喷管的N－S方程计算，发现在型面衔接处有漩涡存在，与最初分析的速度转折点的道理相一致，从而确诊故障。最后，提出型面设计的改进建议，即以余弦曲线代替圆弧曲线，使衔接点处导函数连续，可大大减弱冲刷烧蚀作用，从而避免烧穿。

Abstract:

According to the failure of nozzle burned-through in a large solid rocket motor during ground tests, a series of diagnostic investigation has been carried out. Firstly, the derivative of radius of the nozzle contour along the axis of nozzle is analysed. It is found that, the discontinuity of exists at the joint point of contour curve’ Secondly, a set of comparative simulation tests for nozz1e contour is carried out. It is demonstrated that serious burning erosion occures behind discontinuous point of contour profile in the divergent section. However, burning erosion do not occurs completely in the divergent section without discontinuous point. By using the aeredynamic computation of prototype nozz1e, the eddy system is found in the area near the discontinous point of dirivative of contour profile in the divergent section. A modified contour design of nozzle contour is suggested in the paper. That is, the circular are is replaced by a cosine curve, the derivaction of which is continuous at the joint point of nozzle contour. Thus the nozzle burning-throught can be avoid.