Paper 12: Turbulent Flow and Heat Transfer in Concentric and Eccentric Annuli

Abstract

Fluid flow and heat transfer in non-circular passages, with peripheral variation of heat flux around their boundaries, is of particular interest in the nuclear engineering field. This paper deals with heat transfer to air (Prandtl number ⋍ 0.7) in fully-developed turbulent flow in an annular passage, the outer boundary of which is insulated. Experiments have been conducted on annuii whose radius ratios are 1.632, 2.583, and 3.875 over a Reynolds number range 10 000–50 000. Pressure drop, velocity and temperature distributions in the cross-section have been measured over the whole range of eccentricity of the annulus geometry. The effect of eccentricity on average friction, average heat-transfer coefficient, and wall temperature distribution for uniform heat generation within the heated boundary has been studied. The results of the experimental programme are compared with the semi-theoretical predictions and experimental data of other workers in this field. For completeness, a theoretical equation for the heat-transfer coefficient in an internally heated concentric annulus has been derived.