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.