斜切喷管固体火箭发动机喷管流场与推力特性研究

Characteristics of Nozzle Flow Field and Thrust for a Solid Rocket Motor with a Structure of Angle-Cut Nozzle

关键词:  固体火箭发动机  斜切喷管  推力测试  激波  推力偏转角

Key words:  Solid rocket motor  Angle-cut nozzle  Thrust test  Shock wave  Thrust deflection angle

摘要:

为了研究斜切喷管固体火箭发动机的喷管流场与推力特性，采用二阶精度的AUSM格式求解守恒型N-S方程组并与Realizable k-ε湍流模型相结合，对不同角度斜切喷管的流场特性与推力特性进行数值模拟研究。同时，设计斜切喷管发动机推力测试试验台，通过此测试平台获取发动机工作过程的推力曲线，并与数值仿真结果进行对比，验证所建立的数值仿真计算方法的可行性和有效性。结果表明：通过数值仿真方法获得的斜切喷管发动机推力与试验结果之间的误差较小；由仿真与试验结果可知，45°斜切喷管推力作用线与喷管轴线之间存在夹角，表明斜切喷管发动机存在推力偏转现象。此外，该结构喷管流场存在两个激波交汇高压强区域，同时第二道激波结构强度高于第一道。当喷管斜切角度达到40°时，随着喷管斜切角度的增加，斜切喷管的质量流量、总推力与推力偏转角不断减小，但减小趋势不断变缓。

Abstract:

In order to study the characteristics of nozzle flow field and thrust for a solid rocket motor （SRM） with a structure of angle-cut nozzle， the conservative N-S equations are solved by using the second-order accuracy AUSM scheme， combining them with the Realizable k-ε turbulence model， and then the nozzle flow field and thrust characteristics are researched on the numerical simulation method for different degrees of angle-cut nozzle. At the same time， a thrust stand for the thrust test of angle-cut nozzle SRM is designed. The thrust curve of engine working process is adopted by this thrust stand， and it is compared with the numerical simulation results and the effectiveness and feasibility are verified for this competing method accordingly. Results show that the error between the thrust of angle-cut nozzle SRM obtained by the numerical simulation method and the test results is small. From the simulation and test results， it can be seen that there is an angle between the thrust line and the nozzle axis for 45° of angle-cut nozzle and it has been shown that the thrust deflection phenomenon exists. In addition， there are two high pressure areas which shock waves converged in the nozzle flow field， and the structural strength of the second shock wave is higher than that of the first shock wave. When the degree of angle-cut nozzle reaches 40°， with the increase of the degrees of angle-cut nozzle， the mass flow rate， the total thrust and the thrust deflection angle continuous decrease， but the decreasing trend slows down.