The results of an experimental investigation of the frictional and heat transfer effects for gases passing through heated channels with Reynolds numbers from 200 to 2000 and with values of the ratio of the temperature of the wall to the bulk temperature of the gas up to 2.2 are presented. Local friction factors, not previously available, were found to increase much more rapidly with temperature ratio than predicted by existing analysis [1]. Local heat transfer results are compared to and found to agree with the results of Kays and Nicoll [2]. Previous analyses which include the variation of gas properties with temperature are inadequate to explain the substantial increase in friction factor with temperature ratio. The effects of a postulated radial velocity component are examined and are found to be adequate to explain the friction factor and Nusselt number results.

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