Numerical Analysis of the Improving Thermal Energy Efficiency of Taylor-couette Flow

Abstract

This paper deals with adimensionnal analysis of natural convection in a horizontal cylindrical annulus. The inner cylinder is isothermally heated and rotates with an angular velocity Ω, however the outer one is kept cold and motionless. The gap between cylinders is defined by an adimensional radius ratio f. The numerical study was carried out using COMSOL Multiphysics. The effects of Rayleigh number ranging from 102 to 106, radius ratio and rotation velocity on the flow pattern and the thermal behavior in the annulus are then elaborated. Particular attention is paid to the effect of different parameters on the local Nusselt numbers on the inner and outer cylinders, the mean Nusselt number and the energy efficiency of the process. Results show that the mean Nusselt number increases with the increase of Rayleigh number. However, it decreases with the increase of the radius ratio f because of the narrowing of the annulus. The results prove also that the heat transfer rate drops with the rise of rotation velocity. Finally, it was found that the energy efficiency achieved its maximum for lower Rayleigh numbers Ra=103, and lower rotation velocities.

Energy Efficiency Analysis of Natural Convection Heat Transfer in Concentric Annulus with Interior and Exterior Grooves

“…With the advent of industrial advancement, the continuation of research and studies of convective heat transfer must meet the requirements of recent environmental and industrial applications in terms of improving thermal performance and energy efficiency of processes. In this context, [26], [27], studied numerically the case of concentric and eccentric annulus respectively. The inner cylinder is supposed to be hot and rotating, however the outer one is cold and immobile.…”

Improved Energy Efficiency of Mixed Convection Heating Process in Eccentric Annulus

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