COMPUTER VISUALIZATION OF FLUID CIRCULATION IN ANNULI OF HEATED ROTATING CYLINDERS OF LOW PRANDTL NUMBER FLUIDS

摘要

The present work considered fluid circulation in an annular region between two cylinders with the inner cylinder heated and rotating. The Prandtl number (Pr) considered here varies from 0.01 to 1.0 and Rayleigh number (Ra) is of the order of 10~5. Reynolds number Re in the range of 0 to 1120 was considered. Mono-thermal plume above the stationary inner was observed for higher Prandtl number fluids (Pr0.1) while bi-thermal plume above the stationary inner cylinder was observed for lower Prandtl number fluids (Pr0.1). However, when the inner cylinder is made to rotate, the thermal plume for higher and lower Prandtl number fluids were observed to move in different directions. The mechanism of the mono- and bi-thermal plumes movements were investigated through numerical flow visualization. The application of these studies with rotating inner cylinders are typically encounter in the food and medical processing industries.