低温推进剂贮箱增压过程的传热传质数学模拟

针对火箭发动机地面试验中低温液氧贮箱的预增压和增压过程建立了气相空间的传热、传质数学模型.运用实际气体的状态方程、连续性方程、能量守恒方程以及推进剂与气相空间的传热、传质方程等组成了关于气相空间参数的微分方程组,并运用四阶Runge-Kutta算法对其进行求解.获得了气相空间的压力、温度、增压气体流量、液氧挥发速率以及贮箱壁温等参数的变化规律.结果表明,在发动机启动前的预增压过程中,气相空间的温度和压力急剧增加,液氧的挥发速率也增加很快;发动机启动后的保持增压阶段,由于气相空间的体积不断发生变化,气相空间参数的变化趋于平缓,液氧表面向气相空间的传质速率也趋于稳定.

Simulation of heat transfer and mass transfer in cryogenic propellant tank pressurization process

The model of pre-pressurization process and pressurization process of cryogenic propellant tank in the rocket engine ground experiments was built ; the mass transfer model and heat transfer model among gaseous proportion and cryogenic oxygen were projected in order to obtain the variation laws about the parameters, such as pressure and temperature in the gaseous proportion, gas flux of pressurization nitrogen and oxygen flux of volatilization, vessel temperature and so on. Differential equation group is comprised of actual gas state equation, continuity equation, conversation of energy equation, mass and heat transfer equations. The differential equation group was calculated by the means of four step Runge-Kutta Method. As a result of computation, pressure and temperature of gaseous proportion changed tempestuously in the prepressurization process before engine start and the rate of liquid oxygen volatilization increased rapidly, too. However parameters varieties tend to stabilization in the moment of experiments pressurization, and mass transfer on surface of liquid oxygen tends to stabilization, too.