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为了对发动机燃烧不稳定性进行被动控制,利用亥姆赫兹声学共振器原理,设计一种声学阀门,当一个管道侧面安装的亥姆赫兹共振器的空腔壁面是柔软的时候,声学阀门的性能与频率就没有很强的关系,从而实现由于热声学不稳定带来的压力和热释放导致的不稳定燃烧进行被动控制。阀门的功能是让声音通过,但它必须阻止时间平均意义上的流动。本文对带有这种装置的热声学特征根问题给出数值解。结果显示声学阀门对燃烧室内的驻波结构造成很大改变,进而可以消除不稳定的特征根模态。只要阀门具备足够的尺寸,这种效果可以在任意的线性火焰声学特性中广泛实现。
In order to passively control the engine combustion instability, an acoustic valve is designed using the Helmholtz acoustic resonator principle. When the cavity wall of the Helmholtz resonator mounted on the side of a pipe is soft, the performance of the acoustic valve There is no strong relationship with the frequency, so as to achieve due to the thermoacoustic instability caused by pressure and heat release caused by unstable combustion of passive control. The function of the valve is to let the sound pass, but it must stop the flow of time in the mean sense. In this paper, we give a numerical solution to the thermoacoustic eigenvalue problem with this device. The results show that the acoustic valve greatly changes the standing wave structure in the combustion chamber, and thus can eliminate the unstable eigenmode. As long as the valve is of sufficient size, this effect can be widely implemented in any linear flame acoustics.