Effect of a new pattern of surface roughness on flow field and erosion rate of a cyclone

This paper evaluates the impact of a special design of non-uniform surface roughness on the operating parameters of a gas–solid cyclone numerically. The cyclone surface is divided into 32 separate rings with different roughness heights when the roughness height varies from 0.2 to 3 mm. The results show that the tangential velocity is reduced and the axial velocity is enhanced by increasing the height of non-uniform roughness. It is observed that the cyclone with smooth walls can collect 7 μm solid particles while 3.7 and 2.77 μm particles can be separated by one-inlet and two-inlet cyclones, respectively. For the cut-off size diameter of d 50, the one-inlet cyclone with smooth walls can collect the particles with a diameter of 1.24 µm, while the cyclone with R Nu = 0.2, 0.5, 1, 2, and 3 mm can collect 1.3, 1.6, 1.8, 0.83, and 1.88 µm particles, respectively. The results demonstrate that the erosion rate decreases with the roughness and this reduction is larger for the one-inlet cyclone.