Numerical investigation of combined effects of radiation and convection heat transfer from tube banks placed in a participating medium

Abstract

In the present study, combined convective and radiative heat transfer from in-line tube banks placed in an absorbing, emitting and isotropically scattering participating medium was numerically investigated. The governing flow and radiative transfer equations were solved numerically by utilizing the finite volume methodology and the P1 approximation. The flow is laminar, and the tube walls are black and isothermal. The parameters affecting the heat transfer in such media are the tube pitch, scattering albedo, Reynolds number and conduction-to-radiation parameter. Numerical simulations were carried out for Reynolds numbers between 100 and 300, and the transversal and longitudinal pitches ranging from 1.5D to 3-D, respectively. Also, the medium related parameters such as scattering albedo and conduction-to-radiation parameter were ranged between 0 to 1 and 0.0367 to 0.5080, respectively. The effects of the change in scattering albedo, conduction-to-radiation parameter as well as flow characteristic and tube pitch on temperature distribution and heat transfer were examined. The convective and radiative heat transfer from tubes is analyzed via the surface averaged mean Nusselt number over the whole tube wall. The lowest and the highest total-radiative Nusselt number values were achieved as 3.66-0.091 in the purely scattering medium and as 32.95-25.14 in the non-scattering medium, respectively. Also, a novel correlation (with a coefficient of determination of 0.99804) for tube banks subjected to convection and radiation in a participating media was developed.