液体火箭发动机推力室冷却通道传热优化计算

Numerical optimization simulation on heat transfer in cooling channel of H2/O2 liquid rocket engine thrust chamber

关键词:  液体推进剂火箭发动机  湍流模型  推力室  再生冷却  通道  优化分析

Key words:  Liquid propellant rocket engine  Turbulence model  Thrust chamber  Regenerative cooling  Channel  Optimization

摘要:

采用标准k-ε两方程湍流模型对液体火箭发动机推力室再生冷却通道三维湍流流动与传热过程进行了数值预测,冷却工质为氢气,其密度、导热系数、动力粘度随着温度和压力而变化,通过两种优化方案来改变推力室冷却通道的深宽比。方案一为保持冷却通道的深度及肋宽不变,通过改变推力室壁面通道个数来改变通道的深宽比,方案二为保持通道数目不变,通过增加或降低通道高度来改变通道的深宽比。以此计算在不同通道深宽比下推力室壁面的传热特性,并进行了优化分析。计算结果表明:存在着一个最佳冷却通道个数,使得推力室壁面再生冷却效果达到最佳;在相同质量流量下,降低通道高度能够强化推力室传热,但同时增加了进出口压差。

Abstract:

Turbulent fluid flow and heat transfer in a regenerative-cooling channel of H₂/O₂ liquid rocket engine were numerically investigated by solving three-dimensional elliptical Navier-Stokes equations and the standard k-ε turbulent model was adopted.The coolant was hydrogen,whose thermal properties such as thermal conductivity,density,dynamical viscidity,etc were varied with both temperature and pressure.Two optimized calculation schemes were applied so as to find the best design for rocket combustion chamber.The first scheme was that keeping thickness and height of rib constant,changing the cooling channel number so as to change the aspect ratio of cooling channels.The second one was that keeping the channel number and mass flow rate constant,changing the height of channel so as to change the aspect ratio of cooling channels.The simulation result shows that exist an optimal number of cooling channel which optimize the heat transfer effect of rocket combustion chamber.Heat transfer of rocket chamber will be enhanced when height of cooling channel is reduced,while the pressure drop will increase at the same time.