Measurements of particle velocity and solid concentration near the wall of a cyclone using high-speed particle shadow velocimetry

Abstract

The particle velocity and solid concentration distribution in the near-wall region of a cyclone separator was experimentally studied. A series of measurement experiments were conducted based on the high-speed particle shadow velocimetry (HPSV) method. The experiment was conducted on a ϕ160 mm cyclone at an inlet velocity of 12-20 m/s and inlet concentration of 30-300 g/m3 with glass beads whose median diameter was 136.7 μm. The measured results of the microscopic particle movement demonstrate the moving behavior of the spiral particle band near the cyclone wall. It was found that the particle velocity and solid concentration are greatly different from those in and outside the particle band. The particle velocity inside the particle band can drop to 1.9 m/s, while the dispersed particle velocity outside the particle band away from the wall can reach 15.2 m/s. Along the downward movement of particle band, the particle velocity decrease and velocity fluctuation become milder, the solid concentration increases four times and reaches the highest at the cone wall. On the cross-section plane, the solid concentration decreases along the radial direction away from the wall. In the near-wall region inside particle band, the solid concentration can reach 0.004 or even higher, which is 32 times higher than the inlet solid concentration. This study helps to understand the complex gas-solid two-phase flow phenomena in cyclones.