Study on gas-solid flow behaviors in a spouted bed at elevated pressure: Numerical simulation aspect

Numerical simulations of gas-solid flow behaviors were carried out in a pressurized conical-cylindrical spouted bed with absolute pressure elevated to 1.0 MPa. The three-dimensionally coupled computational fluid dynamic (CFD) technology and Eulerian two-fluid model (TFM) were adopted to model the complex gas-solid flow. The results show that the local minimum spouting velocity (ums) decreases with increasing pressure, while the corresponding gas mass flow rate presents an increasing trend. Simulations conducted with local inlet gas velocity of 1.2ums for varying pressure conditions indicate that an increase in the pressure causes an increase in the fountain height, and the fountain is quicker to be established in simulation time and more stable at higher pressures. The particle velocities have the similar varying tendency along the central axis under different pressures, but in the decelerating region, the deceleration rate of lower pressures is bigger than that of higher pressures. The radial profiles of the particle velocities and concentrations show that the particle velocities decrease with increasing pressure in the lower bed levels, but increase in the upper ones. Conversely, the particle concentrations increase with increasing pressure in the lower bed levels, but they decrease in the middle and upper bed levels. In addition, the defined spout diameter appears to increase with the pressure increasing.