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題名 | 具單一多孔介質突出物管道內紊流熱傳之數值模擬 |
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作者 | 劉通敏; 陳世輝; | 書刊名 | 力學 |
卷期 | 11:4 1995.12[民84.12] |
頁次 | 頁319-326 |
分類號 | 440.137 |
關鍵詞 | 多孔性介質肋條; 孔隙大小; 孔隙率; 熱傳性能; Porous rib; Pore diameter; Porosity; Thermal performance; |
語文 | 中文(Chinese) |
中文摘要 | 本文利用一可同時解多孔介質內外流場之多孔介質模式配合k-ε紊流模式以及以 PISO 法處理速度和壓力藕合問題來計算一二維平板管道內流體部份穿過、 部份繞過一多孔 介質肋條的熱流場問題。此二維平板管道之上板絕熱,下板為等熱通量加熱。多孔介質肋條 之寬高比( W/H )為 1.5,肋條高與管道高之比( H/2B )為 0.5, 以管道平均速度和水 力直徑為特徵速度和長度之雷諾數為 28000, 多孔介質孔隙大小從 1 mm 變化到 4 mm,多 孔介質孔隙率為 0.1,0.3,0.65, 0.87,0.95。計算結果顯示本文之方法可定性及定量預 測出先前文獻甚少探討之孔隙率及孔隙大小對管道內流線、壓力降及下板熱傳係數的影響, 其中孔隙大小影響之預測和先前文獻之實驗結果趨勢上一致,而孔隙率變化之影響結果則為 文獻上首次探討。本文結果亦討論了孔隙大小、孔隙率、迴流區大小及位置、穿透過肋條前 後迎風面流量與管道整體流量之比以及熱傳增益之間的相互影響。在所計算之參數範圍內, 當熱傳增益及壓力損耗兩者兼顧時,孔隙率為 0.95 孔隙大小為 4mm 時之熱傳性能最佳。 |
英文摘要 | A porous model of solving flow field inside and around and porous medium simultaneously is incorporated with k- ε turbulence model and PISO method which handles the coupling of velocity and pressure to investigate the flow passing partly through and partly around a porous rib mounted on the upper plate of a channel with an insulated upper plate and heated lower plate. The rib width to height ratio (W/H) was 1.5, rib height to duct height ratio (H/2B) was 0.5, and Reynolds number based on channel hydraulic diameter and bulk mean velocity was 28000. The pore diameter of the porous rib was varied from 1 mm to 4 mm, and the porosity was varied among 0.1, 0.3, 0.65, 0.87, 0.95. The calculated results indicate that the present method can qualitatively and quantitatively predict the effect of pore diameter and porosity on the streamline pattern, local pressure drop, and local heat transfer distribution of the lower plate. The variation of numerical results with the pore diameter is in good agreement in trend with the experimental results published in the literature, and the variation of those with porosity is first investigated in this study. The results further discuss the mutual interactions among the pore diameter, porosity, the size and position of recirculation zone, the flow rate ratio through front and rear face of the rib and the heat transfer enhancement. Among the parameters investigated, the thermal performance is the best when porosity is equal to 0.95 and pore diameter is equal to 4 mm. |
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