HEAT TRANSFER FROM A ROTATING CIRCULAR CYLINDER IN THE STEADY REGIME: EFFECTS OF PRANDTL NUMBER

In this work, effects of Prandtl number on the heat transfer characteristics of an unconfined rotating circular cylinder are investigated for varying rotation rate (alpha = 0-5) in the Reynolds number range of 1-35 and Prandtl numbers range of 0.7-100 in the steady flow regime. The numerical calculations are carried out by using a finite volume method based commercial computational fluid dynamics solver FLUENT. The isotherm patterns are presented for varying values of Prandtl number and rotation rate in the steady regime. The variation of the local and the average Nusselt numbers with Reynolds number, Prandtl number, and rotation rate are presented for the range of conditions. The average Nusselt number is found to decrease with increasing value of the rotation rate for the fixed value of the Reynolds and Prandtl numbers. With increasing value of the Prandtl number, the average Nusselt number increases for the fixed value of the rotation rate and the Reynolds number; however, the larger values of the Prandtl numbers show a large reduction in the value of the average Nusselt number with increasing rotation rate.