COMBINED LAMINAR FORCED CONVECTION AND NONGRAY-RADIATION HEAT TRANSFER TO CARBON DIOXIDE FLOWING IN A NONBLACK, PLANE-PARALLEL DUCT

Abstract

Simultaneous forced convection and nongray-radiation heat transfer to flowing carbon dioxide in a nonblack duct is analyzed theoretically based on our two-parameter wideband spectral model for the absorption coefficients of infrared gases. The validity of the P₁ approximation is also addressed. It is found that, for a nonblack duct, the convective Nusselt number is much larger than for pure confection and that the P₁, approximation somewhat overpredicts the total Nusselt number due to the overestimation of radiation effects, irrespective of the surface emissivity of a duct, but its accuracy is fully acceptable.