液体离心喷嘴动力学特性理论分析

为了研究离心喷嘴在发动机动态系统中的作用,采用线性化法建立了液体离心喷嘴动力学模型,并推导了可以与其他环节相连的离心喷嘴传递矩阵模型。通过文献中的试验数据,验证了所提出的敞口型离心喷嘴模型的合理性。计算结果表明,在同样的压降和尺寸下,相对收口型离心喷嘴,敞口型离心喷嘴出口流量振荡幅值大大降低,滞后相位角较大。喷嘴与供应系统相互作用时,出口流量的谐振频率由供应系统的声学特性决定,但谐振峰幅值大小由离心喷嘴特性决定。增加喷嘴压降,则出口流量振荡幅值降低;在喷嘴压降不变时,提高发动机系统整体压力,则出口流量振荡幅值增大。

Theoretical analysis for dynamic characteristics of liquid swirl injector

The dynamic models of liquid swirl injector were established with the linearized method and the transfer matrix models of swirl injector were deduced for linking with other components to study the functions of swirl injector in the rocket engine dynamic system.The validity of the open swirl injector dynamic model was confirmed by the test data from the reference.The calculation results show that,under the same pressure drop and size,the amplitude of outlet flow rate oscillation of the open swirl injector is much less than the classical swirl injector,but the lagging phase angle is larger.As the injector interacts with its feeding pipe-line,the resonance frequency of outlet flow rate pulsation is determined by the acoustics characteristics of the feeding system,but the resonance peak amplitude is defined by the characteristics of the swirl injector.If the injection pressure drop is increased,the amplitude of the flow oscillation at the outlet must be reduced.In the case of keeping the injector pressure drop in the same level,higher engine system pressure may aggravate the oscillation amplitude of the flow rate at the outlet.