Annals of the Assembly for International Heat Transfer Conference 13
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ARTICLE:
T. Tsuji T. Kajitani ABSTRACT For turbulence characteristics of a natural convection boundary layer in water along a vertical flat plate, measurements such as mean velocities, mean temperature, velocity and temperature fluctuation intensities, Reynolds shear stress and turbulent heat fluxes are carried out with a particle image velocimetry and a thermocouple rake. To confirm measurement accuracies of these statistics, a direct numerical simulation for a time-developing natural convection boundary layer is also conducted. The measured results coincide relatively well with those obtained from the direct numerical simulation and, consequently, it is found that the turbulence characteristics of the boundary layer in water are similar to those in air, although the turbulent heat fluxes become fairly smaller than those for air due to the effect of high Prandtl number. Moreover, the possibility of heat transfer enhancement of the turbulent natural convection boundary layer is examined by inserting a split heat transfer promoter consisting of short flat plates aligned at fixed intervals into the boundary layer, and it is recognized that the heat transfer coefficient downstream of the promoter exhibits locally increases up to approximately 37 % as compared to that without promoter. TRB-08 pages |
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