氢氧火箭发动机喷雾演化过程作用机理

Study on Mechanism Controlling Spray Evolvement in a Hydrogen/Oxygen Rocket Engine

高压超临界喷雾演化过程作用机理是氢氧火箭发动机燃烧不稳定性机理分析、提高燃烧效率研究的基础。为探讨高压条件下液氧喷雾演化过程的主要作用因素,引入气液同轴喷嘴雾化模型和高压蒸发模型,考虑超临界条件下液氧/气氢气液平衡及其物理属性,对氢氧火箭发动机单喷嘴工况条件下喷雾燃烧过程进行了一体化三维数值仿真,得到了液氧喷雾液滴分布和燃烧流场参数,综合分析了液氧液滴蒸发率、氢氧化学反应率、混合燃气涡量分布与液氧喷雾尺寸、数量的变化规律,提出了液氧喷雾演化过程六个作用因素不同的阶段。

The spray evolvement mechanism of hydrogen/oxygen rocket engines at high pressure supercritical conditions is the basis of analyzing the mechanism of combustion instability and increasing the combustion efficiency.To discuss the main mechanism controlling liquid-oxygen（LOX） spray evolvement,the 3-D integrative turbulent two-phase spray and combustion flow fields at operational conditions of a single element in a hydrogen/oxygen rocket engine were numerically studied. The special spray model for the gas-liquid shear coaxial injector and the evaporation model for high pressure conditions were adopted.The gas-liquid phase equilibrium,thermodynamics and transport properties at supercritical conditions were computed.The distribution of LOX atomized droplets and parameters of combustion flow fields were obtained.Analyzing the influences of evaporation rate of droplets,combustion rate and gas-fired eddy on the dimension and number of spray droplets,the mechanism controlling spray evolvement is described by six phases.