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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.

This work experimentally investigates the heat transfer characteristics of Taylor–Couette–Poiseuille flow in an annular channel by mounting longitudinal ribs on the rotating inner cylinder. The ranges of the axial Reynolds number (Re) and the rotational Reynolds number (ReΩ) are Re = 30–1200 and ReΩ = 0–2922, respectively. Three modes of the inner cylinder without/with longitudinal ribs are considered. A special entry and exit design for the axial coolant flow reveals some interesting findings. The value of Nusselt number (Nu) is almost minimal at the inlet of the annular channel, and then sharply rises in the axial direction. The average Nusselt number ( Nu ¯ ) increases with Re. Nu increases rapidly with ReΩ at low Re (such as at Re = 30 and 60) but that the effect of ReΩ decreases as the value increases (such as at Re = 300–1200). The ratio Nu ¯ / Nu ¯ 0 increases with ReΩ and exceed two at all Re and in the test modes. The heat transfer is typically promoted by mounting longitudinal ribs on the rotating inner cylinder, especially at Re = 300 and 600. When Re = 300 or 600 and ReΩ > 2000, the Nu ¯ of the system with ribs reaches around 1.4 times that of Nu ¯ A ( Nu ¯ in mode A). Under a given pumping power constraint (PRe3), the Nu ¯ of the system with ribs (modes B and C) generally exceeds that without ribs (mode A), while the difference between the values of Nu ¯ in modes B and A slowly falls as PRe3 increases. Additionally, mode B (with ribs) is preferred for high heat transfer when PRe3 4.5 × 1013.