Flows Generated by Critical Opposing Thermosolutal Convection in Fluid Annular Cavities

Brahim El moustaine; Abdelkhalek Cheddadi

Authors

Brahim El moustaine Modeling of Energy Systems, Materials and Mechanical Structures, and Industrial Processes MOSEM2PI-EMI,MohammadiaSchool of Engineers, Mohammed V University, P.O.Box 765, Agdal, Rabat, Morocco
Abdelkhalek Cheddadi Modeling of Energy Systems, Materials and Mechanical Structures, and Industrial Processes MOSEM2PI-EMI,MohammadiaSchool of Engineers, Mohammed V University, P.O.Box 765, Agdal, Rabat, Morocco

Keywords:

Annular cavity, thermosolutal convection, multicellular flows, opposing buoyancies, finite differences, moderate aspect ratio

Abstract

A two-dimensional numerical study has been performed to investigate thermosolutal convection in an annular space, bounded by two very long cylinders subject to opposing heat and solute gradients, the inner and outer walls being submitted to constant temperature and concentration. Three values of the radii ratio of the cavity have been investigated: R = 1.4, R = 1.6 and R = 1.8. The binary fluid (Pr = 0.7 and Le = 3) is set in motion under the effect of the competition of the opposing buoyancy forces with a ratio N = −1. The coupled governing equa@ons wriAen in vor@city-stream function form are solved by ADI scheme with the finite difference method. We have obtained multicellular regimes due to the severe competition between buoyancy forces of thermal and mass origin. In addition, the increase in the aspect ratio influences the gradual disappearance of the small cells. Moreover, it appears that the multicellular regime and the increase in the aspect ratio both contribute to the improvement of thermal and mass transfer.