喷液式固体火箭发动机的稳定性

STABILITY OF SOLID ROCKET MOTOR WITH SPRAY-LIQUID

关键词:  固液混合火箭发动机  推力控制  稳定性  固体火箭发动机

Key words:  Hybrid propellant rocket engine  Thrust control  Combustion stability  Solid rocket enging

摘要:

提出了一种喷液式推力大小可控的固体火箭发动机方案。对反馈控制系统的各个环节建立了运动方程,进而求得时变非线性系统在平衡点的常系数拟线性控制方程,并确定了系统的平衡稳定边界方程和稳定准则。分析指出,喷液式推力可控固体发动机和普通固体发动机在稳定性上有本质差别。小推力工况下发动机工作初期稳定性最差。喷注比或燃烧室自由容积越大,稳定性越好,压强指数在中n和高n值时有利于稳定。

Abstract:

The solid rocket motor (SRM) with spray-liquid consists of control system, liquid oxidant (H2O2) extrusion system and SRM with varied section injector.At certan assumption dynamic equations have been set up for every link of the feedback control system. For time-varied nonlinear system, constant coefficient and quasi-linear governing equations at the equilibrium point have been obtained by zero dimension and linear-ization.By means of transfer function and parameter stability theory, equilibrium steady boundar equations and steady criteria have been determined and solved. Investigation indicates that thrust controllable SRM with spray-liquid differs essentially from conventional SRM in stability. Injection ratio, pressure exponent (n) and tank pressure are main design parameters affecting stability, stability analysis should centre on initial phase of motor oqeration under the small thrust stage. Analysis shows that the larger injec-ion ratio or free volume of combustion chamber is the better stability. And pressure exponent at middle or high n value is favourable to stability.