Open AccessNumerical Analysis of the Improving Thermal Energy Efficiency of Taylor-couette Flow
Author(s) -
Khaoula Ben Abdelmlek,
Fayçal Ben Nejma
Publication year - 2021
Publication title -
wseas transactions on applied and theoretical mechanics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.211
H-Index - 10
eISSN - 2224-3429
pISSN - 1991-8747
DOI - 10.37394/232011.2020.15.26
Subject(s) - nusselt number , annulus (botany) , mechanics , rayleigh number , natural convection , taylor number , heat transfer , radius , cylinder , isothermal process , rotation (mathematics) , streamlines, streaklines, and pathlines , materials science , thermodynamics , physics , convection , turbulence , mathematics , geometry , reynolds number , computer security , computer science , composite material
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.