高压环境下液氧/氢的气-液平衡及其物理属性研究

Research on vapour-liquid equilibrium and physical properties of liquid oxygen/hydrogen mixture at high pressure

在考虑氢气溶解的条件下,运用SRK状态方程计算了液氧/氢在超临界环境下达到气-液平衡时氢氧组分在各相中的摩尔分数以及液氧的蒸发热随液氧表面温度的变化情况;根据气-液平衡时各组分在各相中的摩尔分数,以甲烷为参比态气体,运用扩展对比状态理论(ECST)计算了气相及液相氢氧混合物的pVT属性、黏性及导热系数。结果表明,在高压环境下,有一部分氢气溶解于液氧中,且随着温度和压强的增加其溶解度增大;若考虑氢气溶解,则氢氧混合物的临界温度低于氧的临界温度且随环境压强的增加而减小,这时液氧的蒸发热小于其蒸发潜热,也小于不考虑氢气溶解所得蒸发热。当氢氧混合物达到气液平衡状态时,液相混合物的黏性及导热系数随温度升高逐渐减小,气相混合物的黏性及导热系数随温度升高逐渐增加,最终气相及液相混合物的传输属性在其临界点附近几乎相同。

On the condition of considering the dissolvability of hydrogen, the mole fraction of hydrogen and oxygen on the two phases and the heat of evaporation was computed using SRK equation of state when liquid oxygen/hydrogen reaching the state of vapour-liquid equilibrium at the supercritical environment. Base on the mole fraction on the two phases, the pVT properties, the viscosity and thermal conduction coefficient of the mixture of hydrogen and oxygen was computed using extended corresponding states theory. The result show that a part of hydrogen dissolve in the liquid oxygen and the dissolvability of hydrogen is much larger with the pressure and temperature increasing at high pressure environment; if the dissolvability of hydrogen was considered, the critical temperature of the mixture is lower than the critical temperature of oxygen and it will decrease with the pressure increasing, meanwhile the heat of evaporation of liquid oxygen is lower than the latent heat of evaporation and the result of ignoring the dissolvability; the viscosity and thermal conduction coefficient of liquid phase mixture decrease with temperature rising while the viscosity and thermal conduction coefficient of gas phase mixture decrease with temperature increasing, the transport properties of gas phase and liquid phase mixture is almost equivalent near the critical point of the mixture at last.