為了解決未來電子元件的高發熱量，本研究將微多孔表面應用到雙通漸擴微流道蒸發器上，來得到高性能的蒸發器。並與其他種蒸發器作比較，包含微多孔表面的雙通直線與單通直線微流道蒸發器，以及平滑表面的單通直線微流道蒸發器。微多孔表面由平均粉末大小16 μm的鋁粉膠黏堆疊於流道表面上平均厚度約為 50 μm。 雙通漸擴微流道蒸發器中，相較於平滑表面，微多孔表面因為增加成核孔洞的密度，增強成核沸騰，熱傳性能 較高，但因為較多的汽泡生成，流道容易堵住，使壓降一併上升，在流量100與187 ml/min，燒乾會發生在較低的加熱通率。微多孔表面能對其熱傳效果提升16% ~ 54%，同時壓降亦增加30% ~ 40%。 在雙通流道形式中，相較於直線流道漸擴流道因為第一通的尺寸較小，汽泡更易堵住，造成微多孔表面的漸擴 流道性能比直線差 。 另外將雙通與單通作比較，單通直線流道因為長度比較短所以汽泡 較不容易堵住，使性 能優於雙通的。 實際應用上，若欲用微多孔表面作增強，則可直接施加於單通直線流道上。若管路位置受限，須將入出口設置於同一側，可考慮使用多孔表面的雙通直線流道。;This study applies microporous surface on the two-pass divergent microchannel evaporator to obtain a high performance evaporator for solving high heat dissipation rate electronic devices in near future. The result will be compared with other evaporators, which includes single-pass and two-pass straight microchannel evaporator with microporous surface and single-pass straight microchannel evaporator with plain surface, developed by our lab. The 16 μm average size of aluminum particle is used to make the microporous surface, the average thickness is about 50 μm. Microporous surface increases the nucleation site density, which enhances nucleate boiling and more bubbles are nucleated. While huge amount of bubble will block the channel easier, which causes the higher pressure drop and performance start decreasing at lower heat flux rate. For two-pass divergent microchannel evaporator, the heat transfer coefficient is increased 16% ~ 54% and the pressure drop is increased 30% ~ 40% when microporous surface is applied. Comparison in two-pass channel shows that the heat transfer performance of divergent channel is worse than straight one due to the smaller size of first pass channel which will make the blockage of bubble easier. While comparing two-pass channel to single pass one, the latter one shows the better performance because of the shorter channel length. In practice, apply microporous on single pass straight channel will yield the best performance compared to two-pass divergent and straight channel. Yet, if the inlet and outlet port are constrained to the same side, then two-pass straight channel with microporous surface will be a choice.
