隨著人們對生活品質之要求逐漸提高，家電產品也不斷地創新研發，企圖在性能與節能間尋求平衡，並為人們打造安靜又舒適的生活空間，而家庭必備的電風扇發展至今，也不斷地朝這個目標邁進。本文所探討之無扇葉風扇，有別於以往風扇之設計，其外型簡單極具現代感、無可見之轉動葉輪，相較於傳統電風扇增加了幾分安全性；且少了轉動葉輪便無需加裝安全護網，不僅外型簡潔且清洗也更加容易，上述優點使得無扇葉風扇相當受到矚目。然而其發展至今，鮮少有針對其性能及氣流特性做系統化探討；因此，本研究透過數值模擬進行相關參數分析，以期能取得重要設計參數與其影響。
　　將無扇葉風扇分為引流罩與內部風扇兩個部分進行設計，先針對引流罩之入口條件進行研究探討，並透過數值模擬觀察各項參數變化，對其氣流場及性能之影響；另一方面也進行內部風扇之改良設計，藉由數值模擬分析軟體，針對內部風扇之葉片數、扭轉角、葉輪中心體、導葉片及入口等參數來進行設計，並了解各參數設計方案之成效。而後將兩者最適化之結果整合，以獲得完整之無扇葉風扇最佳化設計，並將此最適化之模型利用CNC加工技術製作，以供進行相關之氣動特性量測與噪音分析，藉此來驗證數值模擬與實驗數據之準確性。
　　所得之測試結果與數值模擬相互比較後，顯示不論是內部風扇或者引流罩，其模擬值與實驗之性能趨勢相當一致，雖然之間有些許誤差，但仍在可接受之範圍內，因此證實數值模擬具有一定的準確度。而與市售樣品之性能進行比較，結果顯示新設計內部風扇之最大壓力高於市售樣品8.9%，最大流量則大幅提升50.3%，而引流罩之組合則提高了25.4%的總引流量。綜合上述之研究成果顯示，本文所設計之無扇葉風扇，已達到整體性能提升之目標，同時規劃出完整之設計方法可供業界作為參考。

　　Appliances are constantly studied and developed with innovative ideas with the intention to furnish a quiet and comfortable living space for people. Recently, the bladeless fan with a simple and modern shape is introduced and becoming popular in the residential fan market. There is no impeller existed in its appearance, so the possible damage caused by the rotating blades is eliminated completely. Besides, this novel design makes the structure simpler and easier to maintain. Obviously, the safety and quiet features are the major reasons for its popularity and acceptance by customers. However, the operating principle and flow characteristics of this bladeless fan are not well understood. Thus this research intends to investigate the physical mechanisms and identify the design parameters of this innovative fan in a systematic manner by a combined effort of numerical and experimental tools.
　　Initially, the Dyson bladeless fan is chosen to analyze its construction and performance measurement for serving as the reference fan. This bladeless fan can be divided into three parts which includes the fan stand, the inducing rim, and the inner fan. Among them the inner fan generates the main airstream to flow through the air path of inducing rim and is the major flow source. The inducing rim provides the appropriate flow passage to create a high-velocity jet for inducing more air stream at the rim exit. Thus, the sum of outlet stream of inner fan and the induced flow around the ring is the total flow rate for this bladeless fan. Clearly, the inner fan and the inducing rim are the key modified portions for enhancing its overall performance and become the investigated topic of this work.
　　At first, several parameters on the geometry of inducing ring, such as the cross-sectional shape, the inclined angle and clearance of air outlet, are studied systematically for enlarging the induced airflow from the rim. Next, an in-line (mixed-flow) fan is selected and designed for serving as the airflow generator (i.e., the inner fan). Note that this new inner fan is an optimized design via a comprehensive parametric analysis on the inlet diameter, the blade number, the twist angle, the central body, and the guide vane. Hence, an adequate design parameter setting of these inducing ring and inner fan is obtained after the aforementioned design procedure and formed the optimized bladeless fan set to yield an improved aerodynamic performance.
　　Furthermore, the prototype of optimized fan design is manufactured by the CNC technique to carry out the corresponding experimental performance verifications. To ensure a reliable outcome, bladeless fan’s performance and noise tests are executed in AMCA and semi-anechoic chambers by following AMCA-210-99, CNS-547 and CNS-8753 codes. Consequently, by comparing the experimental and numerical results, a remarkable agreement between these performance data is observed for verifying the reliability of numerical simulation. Besides, under the same rotating speed, the aerodynamic performance of optimum inner fan is superior to the reference fan by 50.3% and 8.9% enhancements on its maximum flow rate and static pressure, respectively. Also the total overall flow rate of the assembled bladeless fan is improved by a significant 25.4%. In summary, this study successfully establishes a reliable and systematic scheme to design the bladeless fan. Also, the corresponding performance influences caused by those important parameters are analyzed and summed up for serving as the design reference for the bladeless fan.

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