本文利用實驗及數值模擬方式探討電液動( EHD，electrohydrodynamic )技術應用於熱交換器及微泵( micro pump ) 。對於EHD應用於熱交換器方面，利用實驗方法探討電液動技術應用於裸管式熱交換器之增強效果，並與三維數值模擬結果進行比較以驗證本文數值方法之正確性。另外以理論方法探討一外加電場應用於板鰭管熱交換器之電液動增強效果分析。對於EHD應用於微泵方面，本文探討電液動微泵技術應用於微晶片之冷卻技術上之研究，利用數值方式探討此微泵之效能，模擬流體因電場梯度而產生電偶並轉化為拉力，將冷卻液拉動並流經高溫晶片形成一循環冷卻系統。

　　首先，本文針對不同的裸圓管排列(對齊、交錯)和電極排列(正方、對角)，進行一連串之實驗與數值模擬印證。進而利用此套理論模式實際解板鰭管熱交換器，探討EHD對此流場之增強效果。由實驗及數值結果顯示，外加電場的供給電壓增大時，科本因子( Colburn factor j )和摩擦因子( friction factor f )都會增加，但是當流場雷諾數增加時，熱傳增強的效果j/j0及壓損的增加f/f0會隨雷諾數的增加而減少，其中j0和f0為不施加電場下的科本因子和摩擦因子。熱傳及壓降分析上，針對裸圓管部分，數值模擬與實驗分析之誤差約為15% ~ 40%。當裸圓管為對齊排列，電極為正方排列及供給電壓VE = 16KV時，實驗及數值模擬結果之j/j0 = 1.59及1.87，f/f0 = 1.90及1.71。當裸圓管為交錯排列，電極為正方排列時，可得到最佳EHD熱增強效能。當供給電壓VE=16KV時，實驗及數值模擬結果之j/j0 = 1.78及2.25，f/f0 = 2.32及2.00。所以由實驗結果可印證本文所使用之理論模式之準確性。另外，針對板鰭管部分，由模擬結果得知在低雷諾數及高供給電壓時能夠產生最大的EHD熱傳增強效果。另外，交錯形( staggered )管排列方式、正方形( square )電極排列為探討的四種排列中具有最佳的熱傳增強效果。由模擬可知，板鰭圓管在此排列方式且當供給電壓VE = 16KV時，j/j0 = 2.18，f/f0 = 2.12。最後本文亦針對板鰭圓管及板鰭橢圓管進行比較，當供給電壓VE = 16KV，交錯形( staggered )管排列方式、正方形( square )電極排列當中圓管的面積縮減能夠到達55%，而橢圓管的面積縮減能夠到達69%。總體來說在不同的供給電壓下，橢圓管的面積縮減率約為圓管的1.1 ~ 1.9倍，此乃因橢圓管具流線形狀，若放置方向平行於流場則其壓損相對於圓管較小，因此EHD技術應用在橢圓管的效果比圓管佳。

　　針對EHD微泵應用於微晶片冷卻系統上之分析，探討不同電極節距分佈( pitch = 50µm ~ 200µm )，供給電壓( VE = 100V ~ 500V )及工作流體( HFE-7100及oil )之熱傳效果。EHD微泵乃利用正負電極所產生之電偶力驅動冷卻液流經高溫之晶片，並產生一冷卻循環系統及有效地將微晶片之熱量帶走。當pitch愈小，供給電壓愈高，電偶力就愈強，熱傳效果便愈好。其中以pitch = 50µm ; 供給電壓為500V時之熱傳效果最好。其出入口壓力差，熱傳量，流體速度，體積流率及紐賽數分別為12.88 KPa，9.55 W/cm2，0.025 m/s，0.98 L/min-mm2及77.2，其熱傳效率約為pitch = 200µm 之2.5倍。另外，本文亦針對非平行之電極線排列方式所產生之電偶力及熱傳效果進行分析，當正負電極線之角度愈大，其所產生之電偶力便愈大。舉例來說，當pitch = 200µm ; 電極線角度 Ө = 6，其出入口壓力差為pitch = 200µm ; 電極線角度 Ө = 0 之3.03倍。在使用不同工作流體之比較上，當使用HFE-7100時，其熱傳效率約為油的1.29倍。另外針對壁面為定熱通量條件下，不同電極節距( pitch = 20μm，40μm，80μm )之分析，結果發現當節距愈小，其微泵之冷卻效果愈好。但當電極節距降低至20μm時，其所產生之紐賽數及熱傳量僅較電極節距40μm增加10.5%。因此當邊界條件控制為定熱通量及電極節距縮小至20μm時，其所增加之冷卻效果便相當有限了。最後探討EHD微泵對未來微晶片之散熱效果，當電極節距降至5μm時，其熱傳量可達225 W/cm2，其冷卻效率約為電極節距50μm時之17.47倍，這也說明EHD微泵適合應用於現今及未來微晶片之散熱系統。

　This study analyzed the enhanced heat transfer and fluid flow in heat exchanger and micro pump by electrohydrodynamic (EHD) tecnique. The paper discussed the heat transfer in bare tube heat exchanger with EHD enhancement both in experiment and simulation to verify the correction of computational system and the performance of EHD system in bare tube heat exchanger. The paper also analyzed the EHD enhancement applied in plate fin tube heat exchangers numerically. The performance with different configuration of tube and electrode were compared. Finally, the cooling effect for integrated chip using EHD micro pump was also studied for the paper. Different electrodes configuration and working fluid were discussed.

　First, the paper created experimental equipment for bare tube with inlined/staggerd arrangements and square/diagonal arrangements for electrode wires to certify the computational scheme and the performance of EHD system. Then, using the scheme to analyze the effect for the EHD enhancement applies in the finned tube exchanger. For bare tube, the results showed that when the applied voltage = 16KV for the inlined tube with squared electrodes, the experimental and simulated results were j/j0 = 1.59 and 1.87; f/f0 = 1.90 and 1.71. The j0 and f0 stands for the Colburn factor and fanning friction factor, respectively, without EHD enhancement. In other hand, the best performance of EHD implement is for the staggered tube with square electrodes when the applied voltage = 16KV, the experimental and simulated results were j/j0 = 1.78 and 2.25; f/f0 = 2.32 and 2.00. For the comparison between the results for experiment and simulation is about 15% to 40%. The precision of the simulation scheme for the application of the EHD heat transfer implement in the heat transfer tube was confirmed. For the reulsts of finned tube, it was found that the EHD enhancement is more effective for lower Reynolds number and higher applied voltage. The case of staggered tube with square wire electrode arrangement gives the best heat transfer augmentation when applied voltage VE = 16KV, j/j0 = 2.18 and f/f0 = 2.12. In addition, the circular and elliptic tube with EHD enhancement was compared in the study. It indicated a maximum improvement in case of staggered tube with square wire configuration when the VE = 16KV and Reynold number = 100. The reduction in fin area is 55% as compared that without EHD enhancement for ciucular tube and 69% for elliptic tube. It was shown that EHD is more pronounced in elliptic tube.

　Finally, a fully computational system with electrical field, fluid flow and heat transfer for a cooling device by using an EHD micro pump was studied. The micro pump provides the requiring pumping power by using the dipole moment generated from polarizing molecules and induces the flow to cool down the heat source. The computational domain of the micro channel for length and depth were kept in 1500μm and 500μm with parallel electrodes pitch (50μm, 100μm, 200μm with Ө = 0) and with non-parellel electrodes pitch (100μm with Ө = 2 and 200μm with Ө = 6). The effects of different applied voltage VE ranging from 100V to 500V, using HFE-7100 and oil as the working fluid and the temperature difference between fluid and heat source fixed in 50C are investigated in detail. It was found that the EHD micro pump is more effective for lower channel pitch and higher applied voltage. For VE = 500V and parallel electrodes pitch = 50μm, this study identified a maximum performance of 12.88 KPa in the pressure head and 9.55 W/cm2 in the heat transfer. In addition, the performance of liquid velocity, flow rate and averaging Nusselt number for the specific condition were 0.025 m/s, 0.98 L/min-mm2 and 77.2, which is about 250% larger than it is in parallel pitch = 200μm. The study also indicated larger non-parallel electrodes arrangement, which implement more micro pump force. Pressure head with pitch = 200μm and Ө = 6 is about 303% higher than that with pitch = 200μm and Ө = 0. For the comparison of working fluid between HFE-7100 and oil with parallel electrode pitch = 50μm and applied voltage = 500V, the heat transfer for HFE-7100 is 9.55 W/cm2, which is 29% higher compared to that of using oil. The study also analyzed the micro pump effection for different electrodes pitch (20μm, 40μm, 80μm) with the constant heat flux in the wall. The result showed when the electrodes pitch reduced; the micro pump is more effective. However, when the electrodes pitch is 20μm, the heat disspation for the chip is 10.5% higher than it is in pitch = 40μm. So when the electrodes pitch is lower than 20μm, the performance improvement of the micro pump is limited. When electrode pitch is reduced to 5μm, the resutlts showed that the heat transfer could reach 225 W/cm2 which is 17.47 times than it is in pitich = 50μm. It also illustrated that EHD micro pump is a possible application for the future integrated chip.

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