Enhancement of heat transfer using porous convection-to-radiation converter for laminar flow in a circular duct

✍ Scribed by J.M. ZHANG; W.H. SUTTON; F.C. LAI

• Publisher: Elsevier Science
• Year: 1996
• Tongue: English
• Weight: 618 KB
• Volume: 40
• Category: Article
• ISSN: 0017-9310
• DOI: 10.1016/s0017-9310(96)00090-7

✦ Synopsis

The convection-to-radiation converter (CRC) made of porous ceramics has been proven to be an effective means in the enhancement of heat transfer in burners, combustors, industrial furnaces and high temperature plug flow systems. The paper proposes a novel application using this CRC technique in a partial bypass flow system for potential heat transfer enhancement. Hydrodynamically fully-developed and thermally developing laminar flow is assumed in a circular duct which is fitted with a porous core to enhance both convective and radiative transfer from a high-temperature gaseous medium to a heatabsorbing wall. The Navier-Stokes and modified Darcy equations are applied, respectively, to the flow field in a gas layer and porous core region. The radiation field is modeled by a two-dimensional S-type integral equation of transfer for its accuracy and efficiency in the numerical calculations. The effects of heat transfer augmentation using a porous CRC are investigated numerically for various flow and thermal parameters. Numerical solutions which include velocity profiles and flow characteristics of the CRC system as well as isotherm patterns, parameterization of the heat fluxes, mean bulk temperature and Nusselt number distributions along the flow direction are presented. Copyright (\mathbb{C} 1996) Elsevier Science Ltd.