水力直徑與不同形狀流道在強制對流下對微流道熱沈熱傳的影響

Abstract

本論文目的主要在於探討不同形狀微流道的熱傳現象與邊界滑移的效應。在熱傳方面，不同形狀的微流道有不同的熱傳效果，經由模擬發現，微流道的Nu與f•Re兩值會隨著雷諾數與水力直徑的增加而增加，此外在不同形狀的微流道中，矩形微流道的Nu與f•Re比圓形、梯形與三角形的值高。在微流道邊界滑動方面，滑動的產生主要是壁面覆著一層氣體層。本文以三種不同的機制來加以探討，當中發現，氣體以連續體的方式考量下，會背離真實的狀況，若氣體以稀有氣體來假設，因氣體並非連續的覆蓋於壁面，因此可能會產生過度計算的現象，較合理的考量應加入氣體覆蓋於壁面的比例較能符合真實的狀況。

This thesis purposes to investigate heat transfer of microchannels heat sink. The main focus is on two subject. One focus is on heat transfer of different shape microchannel heat sink. The other is the effects of slip boundary on microchannel heat transfer.It is found that Nusselt number and apparent friction constant increase with the increase of Reynold number and hydrulic diameter. The analytical results also show that rectangular microchannel has great Nusselt number and apparent friction constant. For slip boundary of microchannel, it is found that gas intermittent surface coverage much accords with real situation.