高超声速低温喷管横向射流混合反应过程的非定常数值模拟

基于混合RANS/LES (Reynolds averaged Navier-Stokes/large eddy simulation)方法模拟了高超声速低温(HYLTE)喷管倾斜入射横向射流的非定常混合反应过程,研究了不同副喷管喷射角和副喷管间距对射流穿透、混合以及总压损失的影响.计算表明,射流穿透深度和混合程度随着副喷管喷射角的增大而增大,但是总压损失也随之增大;副喷管间距增大,燃料射流的穿透深度增大而且总压损失略有减小,但反转旋涡对(CVP)的集中会造成射流与来流的接触面积减小,侧面混合变差.因此优化副喷管喷射角和间距对于提高HYLTE喷管混合性能乃至激光器光学性能都十分重要.通过模拟HYLTE喷管和光腔耦合区域的12组分23方程的反应流场发现,在中心线附近有较强的小信号增益系数,混合RANS/LES相比RANS方法更能反映流场变量的细节变化. 

Unsteady numerical investigation of mixing and reacting for transverse injection in HYLTE nozzle

A hybrid Reynolds averaged Navier-Stokes/large eddy simulation (RANS/LES) approach was applied to simulate the unsteady mixing and reacting process of the angled transverse injection in the hypersonic low temperature (HYLTE) nozzle,while the influences of different injection angles and distances on the penetration height,mixing and total pressure loss were analyzed.It is found that the penetration height and mixing are enhanced with the increase of the injection angle,but together with the increasing total pressure loss.In addition,when the injection distance increases,the penetration height of the fuel injection increases and the total pressure loss decreases a little,but the counter vortex pairs are too close to produce larger contact regions and better lateral mixing.Optimum incident angle and injection distance are essential to enhance the mixing performance of HYLTE nozzle and optical performance of the deuterium fluoride(DF) chemical laser.Moreover,the reacting flowfield of the coupled region,including 12 chemical species and 23 reactions,was simulated.The small signal gain coefficient reaches the maximum in the vicinity of the centerline.Compared with the method of RANS,hybrid RANS/LES approach is more capable of predicting the changes of flowfield variables.