論文名稱:

充滿黃銅粒堆疊物之矩形通道在不對稱受熱下之熱傳特性實驗研究

Experimental Study of Thermal Characteristics in the Rectangular Channels Fully Packed with Brass Beads at Asymmetrically Heated Condition

研究生:

陳易辰

指導教授:

曾憲中

系所名稱:

機械工程系暨製造科技研究所

          學號:

98017001

畢業學年度:

99

      出版年:

民100

關鍵字:

熱傳 heat transfer

多孔性材料 porous materials

堆疊通道 packed channel

黃銅珠 brass beads

摘要:

本研究以實驗量測方法觀察充滿黃銅粒堆疊物之矩形通道，在不對稱受熱下之熱傳特性，採用空氣為冷卻流體，多孔性材料係使用黃銅珠密實堆疊而成，黃銅珠粒徑(d)尺寸有2 mm、4 mm與6 mm等三種，測試通道寬度(W)固定為60 mm，變動參數為相對堆疊通道長度(L/d=5~60)、相對堆疊通道高度(H/d=1.67~15)與雷諾數(ReD=755~7921、Redp=38~2703)等。實驗結果指出，與通道水力直徑(Dh)相比較，黃銅珠粒徑(d)可能更適合作為整合堆疊通道熱傳數據的尺度參數；此外，粒子紐塞數( )會隨著相對通道長度(L/d)減少而增加，但相對通道高度(H/d)對( )的影響則不敏感；最後，本研究歸納所有實驗數據提出不同相對通道長度(L/d)、相對通道高度(H/d)與粒子雷諾數(Redp)下均適用之平均與局部粒子紐塞數( 、Nudp,x)之經驗修正式。

This study experimentally investigated the heat transfer characteristics in the asymmetrically heated rectangular channels fully filled with porous materials. Air was used as the coolant. The porous materials were packed by brass beads with average diameters (d) of 2, 4 and 6 mm. The channel width (W) was fixed to be 60 mm. Variable parameters were the relative length of packed channel (L/d=5~60), the relative height of packed channel (H/d=1.67~15) and the Reynolds number (ReD=755~7921 and Redp=38~2703). The results indicated that the bead diameter (d), rather than the hydraulic diameter (Dh), may be a proper parameter to generalize the data for heat transfer in a packed channel. Besides, the particle Nusselt number ( ) increased with decreasing L/d, while the H/d was not sensitive to  . Finally, the correlations of average and local particle Nusselt numbers (  and Nudp,x) for various L/d, H/d and Redp were provided.