Fluid flow and heat transfer of natural convection adjacent to upward-facing inclined heated plates

Turbulent transition mechanism and local heat transfer characteristics of the natural convective flows over upward-facing inclined plates were investigated experimentally. The experiments were performed in the range of modified local Rayleigh numbers from 104 to 8 × 1014 and of inclination angles θ from 0 to 90°. The flow fields over the plate and the surface temperatures of the plate were visualized with dye and liquid crystal thermometry. The results showed that longitudinal vortices play a main role in the turbulent transition over the plate of θ < 72°. These vortices appear first in the laminar boundary layer, then detach from the plate and, finally become distorted. It is found that the heat transfer is enhanced markedly by the detachment and the distortion of these vortices. The local heat transfer coefficients were measured in the laminar, transitional, and turbulent regions. The results show that the coefficients in the turbulent region become identical and independent of inclination angles. © 2003 Wiley Periodicals, Inc. Heat Trans Asian Res, 32(3): 278–291, 2003; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/htj.10091