二次启动前火箭发动机泵构件温度特性数值计算

Numerical simulation for the temperature characteristics of turbo-pump system of a rocket engine before the second start-up

关键词:  液体推进剂火箭发动机  涡轮泵  温度计算  集总参数+

Key words:  Liquid propellant rocket engine  Turbine pump  Temperature calculation  Lumped-method~+

摘要:

用数值计算的方法研究了液体火箭发动机在二次启动前,发动机泵系统各构件的温度特性和泵腔含汽率。建立了基于集总参数法的发动机启动前排放过程中涡轮、泵及进口管的温度变化计算模型。排放冷却过程中冷却剂N2O4的单相强制对流换热系数用Dittus-Boelter公式计算,流动沸腾换热系数采用ShanMM强化模型。并对某液体火箭发动机二次启动前排放过程涡轮泵系统各构件温度变化和泵腔含汽率进行了计算,模型计算结果与试车数据吻合良好,研究结果表明,二次启动前的主动排放过程对泵壳体及进口管的冷却效果很好。

Abstract:

A model was developed based on lumped parameter method for numerical simulation of the temperature characteristics of the turbo-pump system of a liquid rocket engine. The turbo-pump system was composed of a turbine, a pump and an inlet tube of the engine. The forced convective heat transfer coefficient for single-phase flow of N₂O₄ was calculated by Dittus-Boelter correlation and the flow boiling heat transfer coefficient were calculated by Shan M M enhancement model. The temperature characteristics of the turbine, the pump and the inlet tube before the second start-up of the liquid rocket engine were obtained by simulation. The quality and the void fraction in pump were also simulated. The simulation results agree well with experimental data. It can be seen that effective cooling of the pump and inlet tube of the liquid rocket engine can be achieved by active discharging before the second start-up.