水平円柱まわりの強制-自然共存対流の熱伝達 : 対向流の熱伝達

概要

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Heat transfer results were presented for the combined forced and natural convection around a heated cylinder placed in the downward flow of water. Local heat transfer coefficients were measured in the range of Reynolds and modified Rayleigh numbers of 100<Red<2500, 1.5×10^6<Ra^*_d<4×10^8. The result demonstrates that the heat transfer rates increase at the lower half of the cylinder with an increase in wall heat flux. Thus, the average Nusselt numbers for the combined convection become 20% higher than those estimated from the pure forced or natural convection. This result is rather different from the results by other workers. The enhancement of the heat transfer rates is explained by the recession of the separation point. Furthermore, the average Nusselt numbers of the combined convection correlate well with the parameter Gr^*_d/Nu_dRe^2_d, and the combined convection region corresponds to the value of this parameter as 0.1< Gr^*_d/Nu_dRe^2_d<10^2.
一般社団法人日本機械学会の論文
1991-11-25