A Study of Natural Convection in a Rotating Enclosure

The local and mean natural convection heat transfer characteristics and flow fields were studied experimentally and numerically in an air-filled, differentially heated enclosure with a cross-sectional aspect ratio of one. The enclosure is rotated above its longitudinal horizontal axis. A Mach-Zehnder interferometer was employed to reveal the entire temperature field, which enable the measurement of the local and mean Nusselt numbers at the hot and cold surfaces. Laser sheet flow visualization was employed to observe the flow field. The result showed that the Coriolis and centrifugal buoyancy forces arising from rotation have a remarkable influence on the local heat transfer when compared with the nonrotating results. Local heat fluxes were obtained as a function of Taylor (Ta≤4×10⁵) and Rayleigh numbers (10⁴<Ra≤3×10⁵), at different angular positions of the enclosure. In addition, a series of interferograms, stream function and isotherm plots demonstrated the strong effect of rotation on the flow field and heat transfer. A correlation of Nusselt number as a function of Taylor and Rayleigh numbers is presented.