Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/2102
標題: 微流道氣流流場與熱傳分析
Analysis of Gaseous Flow and Heat Transfer in Microchannel
作者: 蕭邦佶
Hsiao, Pang Chi
關鍵字: microchannel;微流道;gas;flow;heat transfer;氣體;流場;熱傳
出版社: 機械工程學系
摘要: 
本研究主要目的乃探討氣體在平板微流道中,流動與熱傳的特性。氣體流動由入出口之壓力差來驅動,在流場為層流的範圍內,探討可壓縮性及稀薄效應對氣流與熱傳之影響。
在氣體流動方面,在假設流場為全展之等溫流場時,本研究所得之微流道壓力分佈及速度分佈,與Arkilic et al.(1997)之理論解完全一致。此外,利用質量守恒之觀點,本研究亦得到流量,入出口壓力比,以及管長間之關係式。
在熱傳方面,在假設氣流為不可壓縮時,等壁熱通量及等壁溫度之Graetz問題延伸至探討稀薄效應對熱傳之影響。結果發現,在此兩種條件下,熱全展所需之長度皆較傳統熱傳預測值來得高,且熱傳係數Nu在熱全展時,隨入口Kn數之增加而降低。此外,當考慮氣體壓縮性及稀薄效應時,發現Nu值為管長之函數,在較高之入出口壓力比時,可得較高之Nu值分佈。

The major purpose of present study is to investigate the characteristics of flow and heat transfer in a microchannel. The fluid drived by difference pressure at inlet and outlet in laminar flow to investigate compressibility and rarefaction to case the effect of gas flow and heat transfer.
In flow, the fluid is assumed to be fully-developed and constant temperature. The investigation shows that the pressure distribution and velocity distribution are the same as Arkilic et al.(1997). Furthermore, the present study employs conservation of mass viewpoint, get the relationship between mass flow rate, inlet/outlet pressure ratio, and the length of microchannel.
In heat transfer, the fluid is assumed to be incompressible, the present study is Graetz problem extended to the effect of rarefaction at constant heat flux and constant wall temperature. The investigation shows that the length of thermal fully-developed is longer than traditional heat transfer expected, and Nusselt numbers are decrease with increasing Knudsen number. Furthermore, the study gains Nusselt numbers are function of length of microchannel, and higer Nusselt numbers distribution at higer inlet/outlet pressure ratio when consider effects of compressibility and rarefaction.
URI: http://hdl.handle.net/11455/2102
Appears in Collections:機械工程學系所

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