本研究旨在探討結構誘導聲流效應在不同傾斜角度(α)微流道內的流場特性及熱傳分析。微流道的製作基材為PDMS，結構設計於流道上下壁面交錯排列，並改變結構的傾角為45、60、90、120、135度。實驗利用微粒子影像測速法搭配流場可視化對結構誘導聲流進行流場分析，再透過TSP溫度螢光感測塗料及壓力量測討論熱傳效益與幫浦耗能。本研究先以不同的加熱時間量測液體及壁面溫度變化，以討論在微流道內的熱傳現象，並歸納出流場的溫度穩定時間。
在有誘導效應的流場中顯示，在不同的角度及雷諾數範圍0.5~2的條件下，速度場在結構物附近皆有被擾動的現象，同一個流道於不同雷諾數下，皆隨著主流速度的提升而結構誘導聲流效應會被抑制。在雷諾數為0.5、1、2下，90度結構皆有最大的∆V^*變化，表示在此條件下結構誘導聲流擾動效果最劇烈，而不同角度的聲流效應，由弱至強依序為45、135、60、120、90度結構。後續以微型加熱器施加0.2 W/〖mm〗^2的固定熱通量於流道底部加熱，量測不同傾斜角度在關閉與開啟壓電片的液體溫度變化及入出口的壓力差，以入出口的焓值變化與焓值耗能比分別討論熱傳變化以及熱傳效益，結果顯示在三種雷諾數下，60、90、120度結構在開啟壓片後皆有較大的焓值變化，另以幫浦耗能討論在不同角度的效益，以45、60度有較低的耗能。總體而言，考慮熱傳效益與幫浦耗能的影響，60度結構具有較佳表現。

This study aims to investigate acoustic streaming effect on flow field and heat transfer enhancement in microchannel flow with staggered structures and the incline angles (α) from 45 to 135 degrees at different angles. The microchannel was made of PDMS and the staggered structures were positioned on the side wall of microchannel. The flow field with acoustic streaming was analyzed by Micro Particle Image Velocimetry (Micro-PIV) and flow visualization (FV) technique at the Reynolds number (Re) from 0.5 to 2. The heat transfer analysis and pumping power with acoustic streaming was analyzed by Temperature Sensitive Paint (TSP) and manometer pressure sensors. Due to the profiles of fluid temperature and wall temperature changing with heating process, the experiment was waited up to 3 min to reach steady state. From the flow field result by PIV measurements, the acoustic streaming with staggered structures were suppressed with increase of Re. The acoustic streaming provided most effective disturbance at the 90 degree strucrure. The effect of acoustic streaming on the microchannel flow from weak to strong were 45、135、60、120、90 degree structure.
For the heat transfer analysis, microheaters were used to provide constant heat flux 0.2 W/〖mm〗^2 thermal boundary condition at bottom of microchannel. In order to compare the heat transfer enhancement and discuss the effect with/without acoustic streaming at different structure angles, fluid temperature and pressure differences between inlet and outlet were measured. From the experimental result, the acoustic streaming provided highest enthalpy change with the 60, 90, and 120 degree strucrures microchannel flow between acoustic streaming on and off. However, the 45 and 60 degree structure showed small pressure drop and less pump power required. Due to concern of pumping power required to drive the flow in microchannel, the acoustic streaming with 60 degree strucrure can provided higher heat transfer while requie less pump power.

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