睡眠的相關的疾病中，以阻塞性睡眠呼吸中止症候群(簡稱OSAS)最為困擾人們的生活，臨床經驗顯示經連續正向氣壓通過氣管之管理儀器CPAP，可以有效治療中重度之OSAS患者，而目前CPAP技術主要是以離心風機來提供穩定氣流及壓力。為了使CPAP離心風機具備高性能、高效率及低噪音特性，本研究首先對市售產品進行數值分析與實驗量測，以確定模擬與實驗結果具一致性，由其實驗結果顯示，模擬與實驗誤差在6%以內；接著對外殼流道進行改善，其改善結果藉由Mock-Up之製作測試之後，可得知其操作點壓力及流量分別上升23.3%及11.1%，且消耗功率瓦特數從12.48(W) 降為11.76(W)。至於噪音改善方面，再藉由增強葉輪的結構剛性及增加外殼阻尼，由頻譜圖得知可使葉片第一特徵頻率下降6dB (A)，緊接著加入市售產品之葉輪幾何外型的修改，進行系統化的完整參數分析，舉凡葉片數目、葉片出、入口角度、葉片外型等，探討各個參數對性能的影響，由模擬結果顯示其操作點靜壓、流量及效率分別再度提升5.37%、2.36%與4.21%。歸納來說，本研究之完成可提供在CPAP的設計與開發上全面性地選用高效能、低耗能、低噪音，以滿足設計者之需求，建立一套具系統之分析流程對於提昇CPAP整體性能將有所助益。

Obstructive Sleep Apnea Syndrome (OSAS) is one of the most disturbing sleep diseases. Previous investigations have demonstrated that continuous positive airway pressure (CPAP) can be helpful for OSAS treatment via delivering steady barometric pressure through trachea. Thus, CPAP machine, powered by a centrifugal fan, is considered as the major instrument for offering appropriate air pressure and flow rate to cure OSAS patient, and becomes the research topic of this work. This work aims to establish a systematic fan design procedure for attaining a low noise, high performance, and efficient CPAP. At first, a commercial product is tested experimentally and simulated numerically. It is illustrated that the deviation between these results is an acceptable 6%, which is sufficient to validate the established CFD model, especially considering the correlated trend between two performance curves. After that, a mock-up with housing modification is fabricated and tested to confirm the enhancement of operation condition’s air pressure and flow rate by 23.3% and 11.1%. In addition, the power consumption is reduced from 12.48 to 11.76 W. Also, a 6 dB reduction on the first blade passage frequency is achieved by imposing extra damping system and reinforcing the rotor’s construction. Thereafter, a thorough parametric study on the rotor geometry is executed to examine the corresponding influence on the CPAP performance. The parameters considered here include blade number and geometry, such as its shape, inlet, and outlet angles. In conclusion, the static pressure, flow rate, and efficiency at the operation point are increased further by 5.37%, 2.36%, and 4.21%, respectively.

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