无源腔结构对大膨胀比单膨胀斜面喷管的影响

开展了基于无源腔的单膨胀斜面喷管(SERN)流动控制方法研究,采用标准k-ε两方程湍流模型,通过求解Reynolds平均Navier-Stokes方程,数值研究了过膨胀状态下无源腔结构对SERN内部流场和性能的影响.计算结果表明:与原型SERN相比,落压比为8时,无源腔结构的存在促进SERN上膨胀斜面流动的分离,改变SERN内部流场结构,影响SERN上膨胀斜面压力分布,从而使SERN的轴向推力系数提高1.75%,同时不会带来低头力矩的恶化.在落压比为3~13范围内,无源腔结构的存在促进了无源腔附近附面层流动分离,减少了SERN内激波串数目,并使SERN上膨胀斜面压力峰值增加,提高SERN轴向推力系数. 

Effects of passive cavity on high pressure ratio single expansion ramp nozzle

The flow control method of single expansion ramp nozzle (SERN) was investigated based on passive cavity, and the effects of passive cavity on internal flow field and performance of SERN were numerically investigated under over-expanded condition by solving Reynolds average Navier-Stokes equations, with adoption of standard two-equation k-ε turbulent model. When the pressure ratio value equals 8, the results show that the passive cavity for SERN has evident effects on the flow field structure by encouraging stable separation and affecting pressure distribution on upper expansion ramp wall, thus improving by 1.75% of the axial thrust coefficient of SERN as compared with baseline SERN, meanwhile the nose-down pitching moment does not get worse. Within the range of 3 to 13 of pressure ratio, the passive cavity can enhance the separation of boundary layer near the passive cavity for SERN, and improve the performance of SERN by decreasing the number of shock train and increasing axial thrust coefficient of SERN and pressure peak value distribution on upper expansion ramp wall.