HEAT TRANSFER TO TURBULENT FLOW OF HYDROGEN-CARBON DIOXIDE MIXTURES.

The results of a numerical and experimental study of convective heat transfer for turbulent flow of hydrogen-carbon dioxide mixtures in smooth, electrically heated, vertical circular tubes are presented. Mixtures with molal masses of approximately 14. 5 kg/kg mole were used; this value corresponds to a molecular Prandtl number of about 1/3. Inlet Reynolds numbers were about 34,000 and 83,000, maximum wall-to-bulk temperature ratios about 1. 8 and maximum wall temperatures up to 810 degree K. Results show that popular experimental correlations overpredict the observed Nusselt numbers for constant properties at this Prandtl number. Reynolds' analogy was found suitable for the wall region, for both constant property conditions and the highest heating rates measured.