傳統葉片風扇是透過馬達將電能轉為軸功，再帶動葉片轉為機械能，進而產生氣流。雖然葉片風扇透過這些動件的組合能產生很大的流量及壓降，但也有許多動件相關的缺點，例如葉片與空氣接觸產生的噪音、馬達與葉片所需體積較大、還有轉動與摩擦造成的可靠度問題…等。離子風扇是一種新興的無動件風扇，運作的原理為電液動力學（Electrohydrodynamics）。最簡單的離子風扇可由兩個曲率差異很大的電極組成，曲率大的稱作冠狀電極（Corona Electrode）和而曲率小的為收集電極（Collector Electrode）。當在這兩種電極間加上強電場時（冠狀電極接高壓電，收集電極接地），冠狀電極附近會產生電暈放電（Corona Discharge）的效應，使得通過冠狀電極附近的空氣分子極化而帶電。接著，帶電的空氣分子就會隨著電場往收集電極移動，並且碰撞其他中性空氣分子，重新分配電荷與傳遞動量，造成更多空氣分子帶電而一起往收集電極移動。這股流體運動即為離子風（Ionic Wind）。一般來說，風扇的性能可以用壓力對流量曲線（PQ Curve）來表示。在一般的性能曲線測試標準中，風扇的入口是乾淨無阻礙物的。然而，已經有研究指出，無論是軸流扇或離心扇等葉片風扇，若風扇入口附近有如元件甚至機殼等阻礙物時，風扇的流量跟壓力皆會受到影響而降低。這種影響稱為遮蔽效應（Blockage Effect）。本研究探討針對環型式的離子風扇在不同尺寸及供電方式下（固定電流或固定電壓），其性能（包括流量、消耗電功率、及效率）對入口遮蔽效應的反應。結果顯示，小尺寸之離子風扇無論何種供電方式，遮蔽效應對性能的影響皆不甚明顯；而大尺寸離子風扇在定電壓下受入口遮蔽效應影響較定電流時大。大尺寸離子風扇的流量在有遮蔽效應時會下降，且定電壓流量下降幅度較定電流時為大。另一方面，在定電流模式下，電功率會隨著遮蔽效應的影響有些微增加之趨勢。相反地，在定電壓模式下受遮蔽效應影響時，電功率則會有微幅下降之趨勢。這個現象也說明流量在受遮蔽效應時，定電壓模式下的下降幅度較定電流模式下的下降幅度要大之行為。此外，效率對遮蔽效應的反應與流量相似。大尺寸離子風扇的效率會隨遮蔽效應的出現而下降，且定電壓模式的下降幅度較定電流模式的下降幅度大。本研究的結果說明，小尺寸離子風扇的性能受遮蔽效應影響較小。因此，在系統中應用小型離子風扇時較可忽略遮蔽效應的影響。

本論文主要目的為探討熱交換器之性能分析與探討，進而掌握其相關特性，作為優化或改善之策略。研究中使用spaceclaim改變熱交換器之鰭片開窗數，並使用SolidWorks-Flow Simulation進行模擬分析，以此計算水側與氣側之散熱量，進而找到熱交換器最佳鰭片之設計；並以小型風洞進行水冷散熱之實驗，將實驗數據與模擬數據比對，以驗證模擬分析之數據結果。
熱交換器之鰭片厚度為0.1 mm、長度為24.5 mm，鰭片間距為1 mm，每排為140片鰭片，共有12排。因鰭片開窗會導致網格數增加，使求解時間增加許多，因此先模擬Plain Fin之整體熱交換器，並計算其散熱量後，再以局部熱交換器之Plain Fin與Louver Fin得到其修正因子，最後以修正因子估算Radiator with louver fin之散熱量。
其Louver Fin之開窗數為0、8、16、22、24、26與28個，將散熱量繪製成折線圖，可發現當開窗數為16個時，散熱量已達穩定，因此開窗數大於16個時，對於增加散熱量幫助較小。
由結果可發現，其模擬之氣側與水側散熱量有微小差異，推測其原因為，使用平均密度值計算而造成的差異。模擬與實際量測之散熱量同樣存在些許差異，其原因推測為實際量測之密度為查表得知，因此跟模擬得到的密度會有差異。

This study uses pressure-sensitive paint to determine the effect of an alula-like vortex generator on the surface pressure pattern on the suction side of a thin flat plate. A vortex generator is positioned at the quarter wing span to increase lift, particularly during a deep-stall condition. The low-pressure region is extended because a vortical structure is induced in the presence of a vortex generator so the effectiveness depends on the height of the vortex generator and the angle of attack (attached or separated flow).

Metal organic chemical vapor deposition (MOCVD) is the key technique used for developing thin film materials, such as GaAs, InP, and ZnO, on semiconductor wafers. The technique requires the gas flow, heat transfer, and temperature uniformity on the wafer surface to be carefully controlled, so as to ensure that the thin film’s growth rate is appropriate and spatially uniform. To help serve such needs, a reliable numerical model that allows us to accurately calculate the fluid dynamics and heat transfer in the chambers clearly is highly desirable for MOCVD equipment and process design. In particular, in this presentation we shall focus upon the issue of MOCVD heating system design, which has significant effects on the heat transfer in the chamber, and the thin film’s overall growth rate and spatial uniformity. A good understanding of such effects will enable us to control the power distribution of the heating system effectively, and furthermore optimize the thin film growth characteristics.
Briefly, here the pyrolytic boron nitride (PBN) heaters typically used in MOCVD chambers will be modeled as three independent volumetric heat sources. Then, by using the optimization algorithm based on the gradient method, the power distribution of the three heat sources can be optimized, with an objective function that effectively is the temperature non-uniformity on the wafer surface. Note that the temperature uniformity on the wafer surface is one key factor for the uniformity of epitaxial growth there. Moreover, the sensitivity of the wafer temperature to the gap between the wafer and the isothermal plate (ISP) in the chamber also will be discussed.
Moreover, thin film growth also is calculated in our computations. But to overcome the computational resource limitations, we break down the computations into two parts (see Fig. 1). In the first part, only the flow and thermal fields are calculated. The temperature distributions on the wafer and ISP surfaces then are extracted, and used as the thermal boundary conditions in the second part of computations, in which the chemical reactions and film growth are calculated in a reduced computational domain. One set of the numerical results for film growth rate is shown in Fig. 2. More numerical results will be discussed systematically in the presentation.