Numerical Study of Heat Transfer from Elliptic Tube in a Fluidized Bed

Abstract

In the present work, heat transfer characteristics and flow field from a heated elliptic cylinder immersed in fluidized bed is studied numerically using CFD package. The flow pattern and heat transfer fields around the heated cylinder is predicted using a two fluid Eulerian-Eulerian model coupled with kinetic theory of granular flow (KTGF) with heat transfer. Experiments were carried out under uniform heat flux condition, with air as a fluidizing gas and pulverized coal as a bed material. The Reynolds number based on the equivalent hydraulic diameter, Dh, was ranged from 941to 1263. The simulation results of the present study showed that, for the range of gas velocity considered, at minimum fluidization velocity, Re = 914, the Nuθ is maximum at the sides of the cylinder and minimum at the stagnation, θ=0o, and top, θ=180o, of the cylinder. The average Nusselt number for the elliptic cylinder increases with the increase of the fluidization velocity. The present data is compared with a previous well-known correlation from the literature for a circular cylinder and a reasonable deviation about 11-30% is found.