Theoretical analysis and numerical simulation study on the structural optimization of conical channels in the center tube of a centrifugal radial bed

Abstract

To improve the uniformities of the flow distributions in radial beds, different design methods for conical channels were developed, that is, proportional method, traditional linear method for minimizing the pressure difference between two ends of the channel, newly proposed improved linear method for minimizing the pressure axial variation in the whole channel, and improved multi-segment linear method that divide the channel into multi-segments with different inclination angles. The flow fields under different design methods and gas flow rates are then investigated by numerical simulation. The designation of the angle of the conical channel is particularly significant. Compared to the original structure, the proportional method has difficulty obtaining a proper inclination angle, whose inhomogeneity indices of the distributions of pressure drop η p and gas velocity η v may increase or decrease. The traditional linear method has lower inhomogeneity indices, for example, η v will decrease by ≥7.02%, which denotes more uniform flow distributions, while the improved linear and multi-stage linear methods have the lowest inhomogeneity indices, for example, η v will decrease by ≥12.12 and 13.60%, respectively. Besides, the latter two methods have good adaptability and robustness to fluctuations in the gas flow rate.