Enhancement of heat transfer from a rotating disc using a turbulence promoter.

Abstract

The local and average coefficients of heat transfer and moment coefficients from a rotating disc with turbulence promoters were measured. The experiments covered the range of rotating Reynolds numbers from 103 to 6×104 and were performed using the naphthalene sublimation technique. Two types of promoters, plain rib type and plain rib with slit type, were tested. The conditions of promoters, the height of promoters, the height of slits and the numbers of promoters, were varied. A performance comparison was made of the heat transfer ability from the surface with these turbulence promoters under the condition of constant pumping power. The following results were obtained. The heat transfer coefficients from a disc with a promoter without a slit are enhanced the most. at W/R =0.1. The heat transfer coefficients are enhanced by a suitable slit between the promoter and the surface of the disc. The best performance promoter is the best heat transfer promoter, when the energy loss is considered.