RBCC-RKT两级入轨飞行器起飞质量估算方法

Takeoff Mass Estimation Methods in Two-Stage-To-Orbit RBCC-RKT Launch Vehicle

关键词:  两级入轨  火箭基循环组合发动机  起飞质量  惰性质量比  增广拉格朗日遗传算法 

Key words:  Two-Stage-To-Orbit  RBCC  Takeoff mass  Inert mass ratio  Augmented Lagrangian Genetic Algorithm

摘要:

针对液体火箭发动机真空比冲基本不变,火箭基循环组合发动机(RBCC)比冲随着飞行条件不断变化的特点,提出了将增广拉格朗日遗传算法优化第一级飞行弹道与传统液体火箭质量估算方法估算第二级起飞质量相结合,获得水平起飞两级入轨RBCC—RKT飞行器第一级起飞质量的估算方法, 为总体方案初步设计论证提供参考。通过算例,分析了一级RBCC飞行器惰性质量比、最高动压,气动特性与起飞质量之间的关系。计算表明,降低RBCC飞行器惰性质量比、提高一级飞行器最大飞行动压、提高飞行器升阻比,都能有效地降低一级起飞质量。 

Abstract:

A method for estimating the takeoff mass of RBCC-RKT Two-Stage-To-Orbit(TSTO) horizontal takeoff launch vehicle was established to provide a reference for the scheme demonstration and preliminary design of TSTO vehicle Concept. The second stage takeoff mass was computed by conventional method for estimating multi-stage liquid-propellant rocket engine takeoff mass because vacuum specific impulse of liquid-propellant rocket engine was nearly invariable, while the first stage takeoff mass was optimized with the numerical integration for the motion equations of centroid by Augmented Lagrangian Genetic Algorithm because specific impulse of RBCC changed constantly with the flight condition. Possible factors influencing takeoff mass such as RBCC vehicle inert mass coefficient, maximum dynamic pressure, and aerodynamic characteristics were analyzed. The results show that the first stage takeoff mass will be reduced effectively by reducing RBCC vehicle inert mass ratio, increasing the first stage vehicle maximum dynamic pressure, or increasing the aircraft lift-drag ratio. 