不同类型斜切喷管流场数值模拟

Numerical Simulation on Flow Field of Different Types of Oblique Cut Nozzles

斜切喷管不需要任何附加设备即可产生矢量推力,这一特性可以使得矢量发动机重量减轻,结构更加简单,所以斜切喷管在航空航天领域中的应用越来越广泛。为了研究火箭发动机斜切喷管的喷流特性,建立了一定斜切角度下的锥形斜切喷管和直筒斜切喷管仿真模型,采用有限体积法对两种类型的斜切喷管在不同工作条件下的流场特性进行了数值模拟研究。结果表明:相对于锥形斜切喷管,直筒斜切喷管因为壁面发生转折产生的较强斜激波造成喷管效率降低,在相同的工况下所能达到的最大气流马赫数和速度都要更小,但直筒斜切喷管产生的斜激波使得燃气射流矢量偏转角远大于锥形斜切喷管对应的偏转角,在更加短小的喷管结构下能够提供更大的矢量推力。此外,随着喷管入口压力的增加,燃气所能达到的最大马赫数和射流偏转角也随之增加,燃气射流影响的范围也越大。

Oblique cut nozzles can generate vector thrust without any additional equipment,and this feature can make vector engines lighter in weight and simpler in structure,so oblique cut nozzles are increasingly widely used in the aerospace field.In order to study the jet characteristics of the oblique cut nozzle of rocket engine,simulation models of oblique cut conical nozzle and oblique cut straight tube nozzles at certain angle-cuts are established,and numerical simulations of the flow field characteristics of the two types of oblique cut nozzles are carried out under different operating conditions using the finite volume method.The results show that compared to the oblique cut conical nozzle,the oblique cut straight tube nozzle because of the wall is turned to produce a stronger oblique shock wave caused by the reduced efficiency of the nozzle,in the same operating conditions can achieve the maximum gas jet Mach number and velocity are smaller,but the strong oblique shock wave generated by the oblique cut straight tube nozzle makes the vector deflection angle of the gas jet is much larger than the oblique cut conical nozzle,it also can provide greater vector thrust in a shorter nozzle structure.In addition,as the nozzle inlet pressure increases,the maximum Mach number and jet deflection angle attainable by the gas jet increases,and the range of influence of the gas jet increases.