用于火箭发动机的低温流量控制系统建模及动态特性分析

Modeling and Dynamic Analysis of the Mass Flow Control System Used for Rocket Engine

低温可调汽蚀文氏管是流量控制系统的关键部件,文中选用步进电机控制调节针锥的位移。通过建立步进电机的动力学模型,研究了步进电机的调节速度和调节精度。汽蚀时的流量是几何结构一定的文氏管所能达到的最大流量,文中以此为标准判断文氏管是否汽蚀,并考虑低温的影响,建立了文氏管汽蚀状态和非汽蚀状态下统一的动力学模型。对流量控制系统进行仿真,仿真结果与试验结果的比较,验证了模型的正确性。并利用动力学模型,研究了流量控制系统抗背压波动以及流量调节的能力。

Variable throat venture for cryogenic propellants was the key component for the mass flow control system. And Stcp motor was used to control the displace of the tapered rod.This paper studied the adjust-speed and adjust-pre- cision of the step motor by establishing the dynamic models of it.The mass flow at cavitation was maximal as the geo- metric structure of Venturi was fixed,which could judge if Venturi was cavitated.Based on this fact,uniform dynamic models of throttling Venturi were established when Venturi was cavitated or not.The mass flow control system was simulated,and the comparison with the test results showed the models were correct.This paper also studied the ability to against the fluctuation of back pressure and to control the mass flow by the dynamic models.