乱流域に突起を設置した垂直加熱平板上の自然対流熱伝達

概要

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In the present study, heat transfer coefficients affected with a projection in the turbulent region of a vertical flat plate were measured experimentally for various heights of projections in the range of 0〜20 mm. The wall temperature and fluid flow fields were also visualized using liquid crystal sheet and nylon 12 powder. Average and local Nusselt numbers reach 1.07〜1.22 and 1.2〜1.7 times of those for pure turbulent natural convection, respectively. The maximum enhancement rates of heat transfer are attained in the location of 2.3〜3.3 times of projection height from upper surface of projection towards downstream, and these locations are in good agreement with those of reattachment of fluid flow and center of dark red region in the liquid crystal. On the other hand, the heat transfer coefficients reduce in the just upstream and downstream regions of the projection when compared with those for the no projection. By introducing a nondimensional parameter Ra^*_H, the present experimental results are rearranged quantitatively and effectively.
一般社団法人日本機械学会の論文
1999-12-25