• 대한기계학회논문집
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• 제13권2호
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• pp.299-306
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• 1989

본 연구에서는 밀집형 열교환기에 사용되고 있는 루우버 핀에 해당되는 간단한 형상인 등온, 수직, 평행평판에서의 혼합대류 열전달에 관하여 Pr=0.7, Gr=$10^{4}$ 및 50＜Rｅ$_{L}$＜500인 경유 평판간격과 평판길이를 변수로 하여 유한차분법으로 수치해석하였다. 속도분포, 온도분포 및 Nusselt수를 구하여 평판의 간격과 길이가 열전달에 미치는 영향에 관하여 연구하였다.

• 설비공학논문집
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• 제6권2호
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• pp.155-165
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• 1994

In this study, the following factors are investigated from experiments for a vertical parallel plate heat exchanger under the frosting condition ; the growth of frost layer, the characteristics of heat and mass transfer, the change of mass flow rate of the air passing through the heat exchanger, and the pressure drop of the air in the heat exchanger. The amount of heat and mass flux of water vapor transferred from the air stream to the heat exchanger surface is large at the early stage of frosting and then decreases dramatically, and the extent of decreasing rate becomes moderate with time. The frost layer formed near the inlet of the heat exchanger is thicker and denser than that formed near the outlet. It is found that the gradient of the amount of frost along the flow direction increases with time. In the early period of frost formation, the thermal resistance between the air and the cooling plate increases dramatically and then the extent of change decreases with time. Initially the convective thermal resistance is dominant. Then, while the convective thermal resistance decreases with time, the conductive thermal resistance continues to increase with time and finally the conductive thermal resistance becomes dominant.