Combined Radiation—Convection for a Real Gas

A study of interaction of radiative transfer with convective transfer is presented for slug flow of an absorbing-emitting gas in a circular tube with an isothermal black wall. The zone method of solution is utilized to evaluate axial gas temperature and wall heat flux distributions using recently developed direct exchange areas for arbitrary zone width to radius ratio. Gas radiative properties are evaluated from the weighted sum of gray gases model with weighting factors and gray gas absorption coefficients applicable for an equimolal mixture of carbon dioxide and water vapor. Results are presented for several values of the governing parameters which are the Boltzmann and Stanton numbers, inlet gas and tube wall temperatures, as well as tube length to diameter ratio. Effects of cooling and heating of the gas are examined.