二重円管内密度成層中での自然対流熱伝達 : 外管加熱・内管冷却の場合(熱工学,内燃機関,動力など)

概要

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An experimental study is performed on free convection heat transfer in a stably straified fluid between coaxial cylinders. The stratified layer is formed using a sucrose aqueous solution, and is heated from the outer cylinder at constant heat flux and cooled from the inner cylinder at constant temperature. The experimental results shows that the heat transfer in a stratified fluid is quite different from that in a non-stratified fluid. The effects of the stratification appears conspicuously in the lower part of the fluid : the formation of small cellular convection layers leads to marked deterioration of the local heat transfer coefficient in the lower part, whereas the local heat transfer coefficient increases in the downward for a non-stratified fluid. When the convection layers in the lower part grow thick and contact with the cooling surface of the inner cylinder, the local heat transfer coefficient rapidly increases and approaches that of non-stratified fluid. Mean heat transfer coefficient is governed by such characteristics of the heat transfer in the lower part.
社団法人日本機械学会の論文
2003-09-25