The effect of radiation on the laminar natural convection induced by a line heat source

Abstract

Purpose

To show the effect of radiation from the heat source and the variation of fluid properties on the laminar natural convection induced by a line heat source.

Design/methodology/approach

The governing equations – Navier‐Stokes and energy equation are discretized in a staggered grid by a control volume approach, and they are solved using a segregated technique. The equations for the fluid and solid (line heat source) phases are solved simultaneously. The three sides of the computational domain are open boundary. Some of the physical and thermo‐physical properties of the fluid (air) such as density, thermal conductivity and viscosity were considered to vary with temperature.

Findings

The present predictions are compared with those using the Boussinesq approximation, with the results for the boundary layer equations, and with the experimental results. The present predictions reveal considerable departure from the Boussinesq‐based solution and from the boundary layer results. This study also shows the radiation exchange between the heat source and surrounding has major effect in the results. Thus, the departure between the experimental and analytical results can be explained by the effect of radiation exchange.

Research limitations/implications

In this work, just studied steady‐state laminar thermal plume with the effects of radiation from heat source and the variation of air properties with temperature while it is propose to extend this work to transient and/or turbulent flow.

Originality/value

The effect of radiation from a line heat source on the flow filed around the source and offers enhancement of design to thermal engineers.

Citation

Ayani, M.B., Esfahani, J.A. and Sousa, A.C.M. (2006), "The effect of radiation on the laminar natural convection induced by a line heat source", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 16 No. 1, pp. 28-45. https://doi.org/10.1108/09615530610636946