鉛直角管路内の層流片側冷却における非定常凝固特性 : 浮力の効果による速度分布の変化と凝固に与える影響(熱工学,内燃機関,動力など)

概要

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Numerical and experimental studies on forced and mixed convection heat transfer and freezing for low Reynolds numbers in a vertical duct with asymmetric side-wall cooling at a subzero temperature have been conducted. Numerical results on the ice-layer thickness at steady state were compared with experimental measurements, and a qualitative agreement was observed. It is found that, after the cooling is initiated, a new velocity profile of the main stream, which is formed under the influence of buoyancy, develops in a short time. As the ice-layer grows thicker, however, the parabolic velocity profile is recovered again. The experimental measurements are also in fair agreement with the analytical predictions based on Graetz theory. However, in the experiment, the super cooling always takes place over the entire cooling surface, and it delays the ice formation significantly. The same super cooling was observed at high Reynolds numbers. Consequently, in the growth limit of solidification, the average thickness of ice-layer is found to be proportional to about -1/3 power of the Reynolds number.
一般社団法人日本機械学会の論文
2009-07-25