鉛直角管路内の層流片側冷却における非定常凝固特性（第２報:流速変動に対する固相応答時間）

概要

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Numerical and experimental studies on forced convection heat transfer and freezing in a vertical duct with asymmetric side-wall cooling at a subzero temperature have been conducted. Numerical results of the two-dimensional model with moving boundary were compared with experimental measurements, and a good agreement was observed. It is found that the time required for a steady state after a sudden change of velocity is proportional to about the product of the 1/3 power of movement ratio on ice-water interface multiplied by the minus 1/3 power of the Reynolds number of the main flow. And it is also proportional to the 1/3 power of the distance from the leading edge of the cooling plate. As a fundamental characteristic of the flow, it is shown numerically that a new velocity profile, which is formed under the influence of ice-layer, basically keeps parabolic after the sudden change of the main flow velocity. Therefore, the heat transfer through the liquid-solid boundary may be predicted due to the Graetz theory.