A New Approach to Fixed Bed Radial Heat Transfer Modeling Using Velocity Fields from Computational Fluid Dynamics Simulations

A new velocity-based approach to fixed bed radial heat transfer is presented. Axial and radial velocity components were averaged from detailed 3D computational fluid dynamics (CFD) fixed bed simulations of computer-generated beds of spheres and used to model radial thermal convection. The convection terms were coupled with a radially varying stagnant bed thermal conductivity in a 2D pseudocontinuum fixed-bed heat transfer model. The usual effective radial thermal conductivity k(r) and apparent wall heat transfer coefficient h(w), were not used, and there were no adjustable parameters. The radial and axial temperature variation predicted by the velocity-based model agreed well with the angular-averaged temperatures from the detailed 3D CFD simulations over the range 80 <= Re <= 1900 and for N = 3.96, 5.96, and 7.99.