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

Simultaneous forced convection and nongray-radiation heat transfer to flowing carbon dioxide in a nonblack duct is analyzed theoretically ba sed on our hue-parameter wideband spectral model for the absorption co efficients of infrared gases. The validity of the P-1 approximation is also addressed. It is found that, for a nonblack duct, the convective Nusselt number is much larger than for pure convection and that the P I approximation somewhat overpredicts the total Nusselt number due to the overestimation of radiation effects, irrespective of the surface e missivity of a duct, but its accuracy is fully acceptable.