CFD modeling of heat transfer and hydrodynamics in a draft tube conical spouted bed reactor under pyrolysis conditions: Impact of wall boundary condition

In the present study, the hydrodynamics and heat transfer parameters of a conical spouted bed with a draft tube were investigated under the pyrolysis conditions using computational fluid dynamics (CFD) technique. The Eulerian-Eulerian approach in conjunction with the kinetic theory of granular flow (KTGF) was applied, and some important parameters, such as pressure drop, solid volume fraction, particle velocity, and heat transfer coefficients between the wall and the bed were evaluated. The impact some solid-wall boundary conditions, such as specularity coefficient (phi), and particle-wall restitution coefficient (e(w)), have on the heat transfer and hydrodynamics of the bed were studied. The CFD predictions were in close quantitative agreement with measurements in terms of heat transfer coefficients and pressure drop. It was found that both specularity and particle-wall restitution coefficient have a significant influence on the pressure drop and heat transfer coefficients, with the effect on pressure drop being higher than on heat transfer coefficients. (C) 2017 Elsevier Ltd. All rights reserved.