燒結毛細結構在熱管內之熱流特性

Hydraulic and Thermal Characters of Sintered Wick Structures in Heat Pipes

汪永川(Yung-Chuan Wang)

指導教授 ： 許文震

國立清華大學/工學院/動力機械工程學系/碩士(2006年)

https://doi.org/10.6843/NTHU.2006.00549

摘要

本研究已建立熱管毛細結構相關參數和熱管性能量測
設備，而在熱管內部流場觀測已有初步結果，希望能藉此作
為增強熱管性能及了解其內部物理現象之研究基礎。所架設
之毛細結構性質量測，包含了最大有效孔徑、滲透度及孔隙
度等參數。在熱管性能量測上，於不同加熱瓦數下，調整水
套冷卻能力，如冷卻水之入口溫度或是流量，來固定待測熱
管二分之一長度位置的溫度，並記錄其熱阻，若在某加熱瓦
數下，熱阻值突然變大則判定為乾涸(dry out)，以此量測方
法，才能精準判斷熱管之性能以及不同熱管之性能比較。實
驗結果顯示， 以球形銅粉搭配鬆裝燒結法所製作之毛細結
構，當粉末粒徑愈小，其最大有效孔徑也愈小，雖然可以產
生較高之毛細壓力，但相對的也會造成工作流體在毛細結構
中，流動阻力上升，滲透度下降，而經由熱管性能測試後，
發現粉末粒徑愈大之熱管，蒸發端溫度愈低，而且其在不同
角度下皆有較好之熱傳量，由此可知，滲透度對於粉末燒結
式熱管性能的影響大於毛細壓力， 特別是當熱管長度愈長
時，滲透度之影響更為顯著。

關鍵字

熱管 ； 毛細結構 ； 有效孔徑 ； 滲透度

並列摘要

The thermal performance of heat pipes and the capillary
structure parameters such as the pore radius, the permeability
and the porosity are investigated experimentally in this work.
In addition, there is a preliminary result of flow visualization
available in the plate heat pipe. For the measurement of
performance of heat pipes, the middle point of heat pipes is
maintained at constant temperature by adjusting the cooling
capacity, and then the thermal resistance is recorded at varied
power level. When the thermal resistance suddenly rises to a
great value, the dry-out phenomena will occur in the heat pipes.
Based on this measurement method, we can obtain the
maximum heat transfer rate of heat pipes and compare with
each other. The wick structures are made by a sintering process
with spherically loose copper powders of different sizes. The
results show that the process with fine particles gives a small
pore radius and permeability respectively. The heat transfer
rates of heat pipes are greater for the wick with larger particle
sizes. According to the present results, the performance of heat
pipes mainly depends on the permeability rather than the
capillary pressure especially for long heat pipes.

參考文獻

Fluid Mechanics, John Wiley & Sons, Inc., New York.

1991, “Design of High-Performance Sintered Wick Heat

Pipes,“ International Journal of Heat and Mass Transfer, vol. 34,no. 6,

4.M. P. Mughal and O. A. Plumb, 1996, “An Experimental Study of

Analyses of Flat Miniature Heat Pipes,” Energy Conversion