关键词: 旋风分离器, 流场, 热线风速仪, 灰斗, 速度波动, 主频

Abstract:

The dust exhaust port at the bottom end of the cyclone separator adopts an ash or ashless bucket structure according to the requirements of the gas-solid separation process. The existence of the hopper has an important influence on the flow field inside the cyclone separator, and then the separating performance. But the research of this aspect is few. Therefore, the tangential velocity of gas flow field in the cyclone separator with and without hopper was measured by using hot wire anemometry (HWA). The results show that the swirling flow in the cyclone is highly instability, and the real tangential velocity fluctuates with low frequency and high amplitude. Further, the existence of hopper leads to strong instability of swirling flow field near the dust outlet, which is characterized by intense fluctuation of real tangential velocity. Fast Fourier transform analysis of measured data shows that the real tangential velocity of cyclone separator with hopper has two dominant frequencies, one exists in the whole space and another one presents in the local area near the dust outlet. However there is only one dominant frequency in the whole space of the cyclone without hopper. The dominant frequency of the whole space is caused by the swing of the swirling flow center around the geometric center, while the local dominant frequency is caused by the backflow from the hopper. So, the swing of the swirling flow from the hopper is superimposed on the swing of the swirling flow in the separation space, which forms two dominant frequencies near the dust outlet region.

Key words: cyclone separator, flow field, hot wire anemometry, hopper, velocity fluctuation, dominant frequency