Fluid flow and convection heat transfer in concentric and eccentric cylindrical annuli of different radii ratios for Taylor-Couette-Poiseuille flow

Abstract

This paper presents the results of fluid flow and convection heat transfer in concentric and eccentric annuli between two cylinders using a three-dimensional computational fluid dynamics model. Effects of rotational speed ( n = 0, 150, 300, and 400 rpm) and eccentricity (ε = 0, 0.15, 0.3, 0.45, and 0.6) on axial and tangential velocity distribution, pressure drop and forced convection heat transfer are investigated for radii ratios (η) of 0.2, 0.4, 0.6, and 0.8, Reynolds number 2.0 × 103–1.236 × 105, Taylor number 1.47 × 106–1.6 × 1010, and Prandtl number 3.71–6.94. The parameters cover many applications, including rotary heat exchangers, mixers, agitators, etc. Nusselt numbers and friction factors for stationary and rotated concentric and eccentric annuli are correlated with four dimensionless numbers. The results revealed that when the speed of the inner cylinder increases from 0 to 400 rpm, the friction factor increases by 7.7%–103% for concentric and 8.2%–148% for eccentric annuli, whereas Nusselt number enhances by 37%–333% for concentric and 44%–340% for eccentric annuli. The radius ratio has a substantial effect on the heat transfer and pressure drop in annuli. The eccentricity enhances the heat transfer up to 12%, whereas its effect on the friction factor is not monotonic as it depends on Reynolds number, radii ratios, and rotational speed.

Precipitation of cerianite crystals and its effect on the rheology of a simplified nuclear glass melt

“…36,58 Considering that the Couette analogy implies a virtual inner cylinder (the rotor) and the outer cylinder (the crucible) to determine the calibration factors, a speed gradient is also present in the gap. Therefore, unlike the crystals in the bulk that are transported together with the melt, the crystals growing on the surface of the crucible are fixed and submitted to stronger convection, 59,60 and there is probably a higher amount of Ce 2 O 3 available to be attached in the growing crystals. Regarding their morphology, the sections shown in Figure 10C evidence an initial dendritic crystal that changes towards a cubic shape due to the decrease in the supersaturation of the melt (decrease in the Ce 2 O 3 %).…”

Heat Transport in Rotating Annular Duct: A Short Review

“…The rotational effect of the inner or external wall has resulted in a second class of instabilities. Such flows type are known under the name of Rotor-Stator cavities [6], Taylor-Couette [7] or Taylor-Couette-Poiseuille [8] if an axial flow rate is superimposed to the rotation. They have the particularity of reaching a high level of complexity from the point of view of the turbulence properties.…”