Performance improvement of a cyclone separator using different shapes of vortex finder under high-temperature operating condition

Abstract

In the present study, the effect of inlet temperature on cyclone performance was numerically investigated based on computational fluid dynamics (CFD) approach. The Eulerian–Lagrangian approach in conjunction with the Reynolds stress transport model was employed to solve the unsteady Reynolds-averaged Navier–Stokes equations. A series of numerical simulations were carried out at a wide temperature range of 293 K to 700 K. Conclusive results indicated that the separation efficiency of cyclone significantly decreased with any increment of inlet temperature due to weaker swirling flow across the cyclone at a higher temperature. In this condition, it is essential to find an impressive way to overcome this negative effect. Hence, four proposed shapes, namely divergent vortex finder and convergent vortex finder (CVF) were designed to use instead of base one under high-temperature operating conditions. The results extracted from CFD simulations demonstrated that the maximum tangential velocity was obtained about 2.2 times of the inlet velocity (v = 11.99 m/s) at T = 700 K for cyclone with CVF 1, while it was predicted 1.9 times of the inlet velocity for a base cyclone. Moreover, other cyclones generated tangential velocities even less than the base cyclone. Higher tangential velocity led to increase the centrifugal force and cyclone separation efficiency. Using CVF 1 instead of a base vortex finder significantly helped the cyclone to collect finer particles. Whereas the separation efficiency enhanced 9.5% for the particle size of 2 µm at T = 700 K and v = 20.18 m/s compared to the base cyclone.