分段式无源流体推力矢量喷管线性控制特性研究

The linear control characteristic of the multi-wall passive fluidic thrust vectoring nozzle

  • 摘要: 推力矢量是目前高性能飞行器的关键技术之一,根据实现原理分为机械式和流体式,流体式因结构简单、偏转响应快、能耗小得到了广泛关注。现有的矩形流体式推力矢量喷管存在控制规律突跳、非线性的问题,同时偏转角度有限,限制了该技术的工程应用。本文设计了一种新型的矩形分段式无源流体推力矢量喷管,通过多段壁板的“阶梯式”二次流控制和改变初始被动二次流控制量的两种控制策略,探究该新型喷管能否实现射流高线性度、大偏转角的矢量控制。采用实验和数值模拟相结合的手段对该喷管射流偏转的力学特性和流场特性开展研究。研究结果表明:该分段式矢量喷管通过“阶梯式”二次流控制提高了力矢量角变化曲线的线性度,增大了偏转的可控角度,线性度由62%提高到90.8%,最大射流偏转力矢量角从18°提高到22°;当被动二次流的初始进出气面积比为1.16时,线性度进一步增加到94.9%;该喷管在射流偏转过程中近壁面不存在明显的分离泡结构,初步解释了该喷管线性连续控制射流偏转规律的原理。

     

    Abstract: The thrust vectoring technology is the key technology of high-performance aircraft, which can be divided into the mechanical and the fluidic thrust vectoring technology. The fluidic thrust vectoring technology has advantages of simple structure, fast deflection response and low energy consumption, so it has been widely studied. However the problems of jump and nonlinearity of the control law exist in the current rectangular fluidic thrust vectoring nozzles. Meanwhile the maximum deflection angle is small, which seriously limits the engineering application of this technology. A new type of the rectangular multi-wall passive thrust vectoring nozzle is developed in this paper. In order to figure out whether this new nozzle can realize the vector control of the jet with high linearity and larger deflection angle, two control strategies of the multi-section wall under multi-wall passive secondary flow and the variation of the initial passive secondary flow rate are employed. The characteristics of the dynamics and flow field of the jet are studied by means of experiment and numerical simulation. The results show that these control methods improve the linearity of the control law of the force vector angle, and the effective deflection force vector angle is increased. The linearity of the control law increases from 62% to 90.8%, and the maximum deflection force vector angle increases from 18° to 22°. When the initial inlet and outlet area ratio of the passive secondary flow is 1.16, the line-arity is further increased to 94.9%. It is found that there is no obvious separation bubble structure near the wall of the nozzle during jet deflection, which preliminarily explains the principle of the linear continuous control law of the nozzle.

     

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