Experimental study of gas swirling flow instability characteristics in a cyclone using the hot‐wire anemometry technique

Abstract

AbstractThe instability characteristics of gas swirling flow in a cyclone were investigated experimentally by measuring the instantaneous tangential velocity with the hot‐wire anemometry. The results showed that the instantaneous tangential velocity fluctuated continuously with time at both low and high frequencies. Further analysis of measured data regarding time and frequency domain by probability density and spectral methods revealed that the velocity fluctuation was affected not only by the turbulence flow itself but also by gas swirling flow instability. Also, the distributions of dominant frequency and amplitude indicated that low‐frequency velocity fluctuation caused by the instability had the transfer behavior and attenuation character, which could be characterized by the dominant frequency that varied little along the radial position and decreased gradually along the axial direction, while the amplitude increased significantly with decreased radial position. Due to the gas swirling instability, the turbulence intensity and the fine particle diffusion were enhanced, which would degrade the separation efficiency of cyclone.