CFD Simulation of Heat Transfer from Elliptic Tube Bundle Buried in a Bubbling Fluidized Bed
M. A. Abd-Rabbo
Department of Mechanical Engineering, Faculty of Engineering, Al-Azhar University, Egypt.
R. Y. Sakr
Department of Mechanical Engineering, Faculty of Engineering Shoubra, Banha University, Egypt.
M. A. Mohammad
Department of Mechanical Engineering, Faculty of Engineering, Al-Azhar University, Egypt.
M. M. Mandour
Department of Mechanical Engineering, Faculty of Engineering, Al-Azhar University, Egypt.
*Author to whom correspondence should be addressed.
Abstract
In the present work, numerical simulations are performed to study heat transfer characteristics and fluid flow around elliptic tube heat exchanger. The results for heat transfer coefficient between immersed inline and staggered bundles of horizontal smooth tubes and air-fluidized bed of pulverized coal, dp = 2 mm, are reported within the range of fluidization number, Usup/ Umf, ranges from 1 to 1.4. Heat transfer as well as multiphase flow dynamics in fluidized bed is modelled using the Eulerian-Eulerian and the Two-Fluid Model (TFM) with Kinetic Theory of Granular Flow (KTGF) to describe the granular flow characteristics of the solid phase. The average heat transfer coefficient for the present work is compared with that obtained from the well-known correlation of circular cylinder and a noticed improvement is observed. It is noticed that, the average Nusselt number increases with fluidization number. Also, it is noticed that, the average Nusselt number in case of staggered tubes bundle is higher than the case of inline tubes bundle. The inline tube bundle has lesser pressure drop than the staggered tube bundle.
Keywords: Heat transfer, CFD, elliptic tube bundle, fluidized bed.