凝相粒子相变及微观传热对喷管内两相流动换热的影响规律研究

Effects of phase transition and heat transfer of condensed particles on two⁃phase flows in the nozzle

固体火箭发动机喷管燃气中氧化铝凝相粒子与环境间的传热及凝固过程影响了喷管两相流动换热过程。构建了凝相粒子的微观传热模型—粒子与环境间的对流换热、辐射换热及液-固相变模型,并将粒子微观传热模型与喷管内一维两相非平衡流动模型进行耦合计算,获得了考虑凝相粒子相变及微观传热对喷管内非平衡两相流动传热的影响规律。结果表明:基于Drake模型计算喷管内粒子与环境间对流换热的精度最高,对于粒子而言辐射传热远小于对流传热,占比仅为0.041%。考虑粒子液-固相变时,计算得到的气相和凝相粒子出口温度显著高于不考虑相变的,而出口速度则略为升高。当喷管入口温度为3000 K时,与无相变的结果相比较,气相和凝固粒子的出口温度分别高出25.5%和26.7%,而出口速度则分别高出1.2%和0.5%。

The heat transfer and solidification process between alumina condensate particles in the solid rocket motor nozzle gas and environment have impact on the two⁃phase flow process in the nozzle.The microscopic heat transfer models of the condensed particles were established,including the convective heat transfer,radiative heat transfer and liquid⁃solid phase change models be⁃tween particles and environment.Besides,those heat transfer models were coupled with the one⁃dimensional non⁃equilibrium two⁃phase model of the nozzle to investigate the effects of phase transition and heat transfer of condensed particles on two⁃phase flows in the nozzle.The results show that the Drake model has the best accuracy for calculating the convective heat transfer.For condensed particles,the radiative heat transfer is far less than the convective heat transfer,with a contribution of 0.041%.When considering the liquid⁃solid phase transition of condensed particles,the outlet temperature of gas and particle phases are significantly higher while the outlet velocity is slightly higher than those without considering liquid⁃solid phase transition.At an inlet temperature 3000 K,the outlet temperature of gas and condensed particles is 25.5%and 26.7%higher than that without considering the phase transition,while the outlet velocity is 1.2%and 0.5%higher,respectively.