导流槽构型对火箭起飞时流场和声场的影响

为了研究四喷管运载火箭起飞时火箭周围噪声环境问题,建立燃气/空气双组分的可压缩流动模型,采用2阶Roe格式、SAS(scale-adaptive simulation)湍流模型和声学类比积分法Ffowcs-Williams Hawkings(FW-H)求解三维Navier-Stokes方程。以单机火箭的噪声问题为对象开展数值模拟,并将噪声数值计算结果与试验数据对比,误差在3dB以内(相对误差小于1.6%),验证预测噪声方法的有效性,进而研究四喷管运载火箭起飞阶段采用不同导流槽构型对箭体舱段区域噪声环境的影响,结果表明:在相同噪声接收点处,单侧导流槽对应的总声压级比双侧导流槽大,两者的总声压级(OASPL)之差最大为10.7dB。另外,当采用单侧导流槽时,沿周向接收点的噪声总声压相对单侧导流槽中心截面呈对称分布,而且沿导流出口方向逐渐增大。所建立的噪声数值方法为大推力捆绑运载火箭舱段的噪声环境预测及其控制提供一定参考。

Influence of jet deflector configuration on flow field and acoustics field of launch vehicle at lift-off

To study the acoustics environment around the four-nozzle launch vehicle at lift-off, a two-component compressed flow model of gas/air was established. The second-order Roe scheme, SAS (scale-adaptive simulation) turbulence model and acoustic analogy method (FW-H) were used to solve the three-dimensional Navier-Stokes equation. Firstly, the jet and noise of single-nozzle launch vehicle were numerically simulated. The error between the numerical results and the experimental data was less than 3dB (relative error less than 1.6%), and then the configuration of the jet deflector on the acoustic environment of the four-nozzle launch vehicle was studied. Results showed that the overall sound pressure level of the one-sided jet deflector was larger than that of the two-sided jet deflector, and the maximum difference of the overall sound pressure level (OASPL) was 10.7dB. In addition, for one-sided jet deflector, the overall sound pressure level of the circumferential noise receiving points showed the symmetry of the center section of the one-sided jet deflector and the increasing trend along the direction of the jet deflector outlet. The research results provide some reference for the prediction of noise environment and noise control of launch vehicle.