Performance assessment of a square cyclone influenced by inlet section modifications

Abstract

The main objective of the present study was to analyze the effect of varying the inlet shape on the flow field and overall performance in a square cyclone. Three different inlet shapes, namely straight, inclined, and bend inlets, were specifically proposed to improve the low separation efficiency of the square cyclone. A three-dimensional numerical simulation was done by solving the Reynolds averaged Navier-Stokes equations with the Reynolds stress model turbulence model and applying the Eulerian-Lagrangian two-phase method. The turbulent dispersion of particles was predicted by the application of the discrete random walk model. Comprehensive comparisons of pressure drop, separation efficiency, 50% cut sizes, and flow field were performed to demonstrate the mechanism of how the inlet shape influenced the square cyclone performance. The results extracted from computational fluid dynamics simulation demonstrated that although using inclined and bend inlets produced an increase in pressure drop, they positively enhanced the separation efficiency of the square cyclone. Among all inlet shapes, inclined inlet significantly helped the square cyclone to collect finer particles, as it reduced the 50% cut sizes approximately 29.4% at an inlet velocity of 28 m/s. Keywords Square cyclone • Inlet shape • Separation efficiency • Eulerian-Lagrangian • Computational fluid dynamics (CFD) Abbreviations C D Drag coefficient ν Gas kinematic viscosity (m 2 /s) K Fluctuating kinetic energy (m 2 /s 2) u i Gas velocity in i-direction (m/s) g i Gravitational acceleration in i-direction (m/s 2) P f Fluctuating energy production (m 2 /s 3) μ Gas dynamic viscosity (kg/ms) ρ Gas density (kg/m 3) ρ p Particle density (kg/m 3) R ij Reynolds stress tensor u pi Particle velocity in i direction (m/s) ε Turbulence dissipation rate (m 2 /s 3) v Velocity (m/s) d p Particle diameter (μm) Re p Relative Reynolds number P Pressure (Pa)