上向き傾斜加熱平板まわりの自然対流の流動と伝熱 : 空気の場合(熱工学,内燃機関,動力など)

概要

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Turbulent transition mechanisms and heat transfer characteristics of natural convection over inclined plate heated with constant heat fluxes were investigated experimentally. The experiments covered the ranges of the modified Rayleigh numbers from 10^3 to 8×10^<12> and the inclination angles θ from 0 (horizontal) to 90° (vertical). The flow fields over the plate were visualized with smoke. The results showed that longitudinal vortices appear first in the laminar boundary layer when θ<72°. Then, the vortices detach from the plate and become distorted, and, finally, a fully turbulent state is accomplished at far downstream of the plate. Local Nusselt numbers were also measured under the same conditions of the above visualizations. The results showed that the numbers deviate from the laminar values with the formation of the longitudinal vortices and, then, increase significantly with the detachment of the vortices. Based on these results, empirical correlations for the laminar and turbulent heat transfer by natural convection were proposed.
2009-11-25