Simulation And Analysis On The Two-Phase Flow Field In Rotating-Stream-Tray Absorber By Using CFD Method

Rotating-stream-tray (RST) absorber, which was invented by Zhejiang University, is a high-efficient equipment for mass transfer. Its performance is better than that of commercial absorbers used in developed countries. It has been successfully implemented in fuel gas desulfurization project for large and medium scale coal-burning boiler. The motion of the gas and liquid phases in RST absorber is the main factor affecting its efficiency. The study of the two-phase velocity field in RST absorber is very important and instructive to the further optimization of RST and the amelioration of operating conditions.Based upon powerful computers and commercially available Computational Fluid Dynamics (CFD) software (FLUENT), 3D models of 0150mm and 04000mm RST with plenty numbers of meshes were generated and the two-phase flow fields in RST absorbers were simulated using Eulerian multiphase theory, two-equation RNG K-e turbulence model and granular flow model in this work.Method for mesh generation of RST was studied and optimized. The computational RST models studied in this paper were strictly build and finely meshed.Two phase flow distribution under certain operating condition in 0150mm and 04000mm RST was obtained by using RNG K-e and Eulerian model. The flow field of RST after amplify was questioned for the distribution of water being abnormal.The model of turbulence viscosity of water phase was improved by adopting granular flow model and the model for interphase exchange coefficient was changed. After setting some characteristic droplet diameters, the new flow fields of 0150mm and 04000mm RST were obtained. It was found that the ability of removing small diameter (less than 300um) droplets of large scale RST was relatively limited.The research carried out in this work provided an effective method for the simulation of two phase flow field in RST. The results are helpful to the structural optimization and large-scale designing. Also, the work provided the foundation for further research. Based on this foundation, the CFD simulation of heat transfer and chemical reaction process in RST can be carried out.