橢圓管之管陣流場與熱傳數值模擬研究

Numerical Study on the Thermal-Hydraulic Characteristics of Elliptic Tube Bundle

方建程(Fang Jian-Cheng)；簡良翰(Chien Liang-Han)

橢圓管 ； 數值模擬 ； 熱傳 ； 壓損 ； Elliptic tube ； numerical simulation ； heat transfer ； pressure drop

冷凍空調&能源科技

108期（2018 / 03 / 10）

26 - 31

繁體中文;英文

目前國內大部分蒸發式冷卻器或鰭管式熱交換器之管陣多為圓管，而橢圓管管陣在管外側之壓損較低，有助於提升熱交換器之效能。本研究使用Ansys／Fluent®套裝軟體對橢圓管外之空氣側進行數值模擬，比較橢圓管在不同傾斜角度（0°至90°）下之壓損及總表面熱通量，並與相同周長之圓管比較。模擬結果與實驗值誤差小於10%。模擬結果顯示橢圓管長軸與偏移氣流方向之傾斜角度越大，流場在管後方所產生之渦流越明顯，且熱傳與溫度變化越大，壓損也越大。橢圓管在傾斜角0°時，／值為圓管之2.7至3.6倍。

Currently, most of the tube bundle in the domestic evaporative coolers and fin-tube heat exchangers use circular tube. However, the elliptic tube bundle has the advantage of lower pressure drop on the air side as compared with the circular tube bundle, and hence can improve the efficiency of heat exchangers. This study used CFD package software, ANSYS FLUENT, to simulate the air flow of elliptic and circular tube bundle. Comparing the pressure drop and total heat flux of elliptic tube bundle at different flow angles of attack (0°-90°). The results indicated that, increasing the angle of attack, the vortex formed behind the tube is more obvious. Consequently, the heat transfer, temperature variation, and the pressure drop are also increased. At zero angle of attack, the / of elliptic tube bundle is 2.7 to 3.6 times circular tube bundle.

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