| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 88 === The purpose of this study is to investigate a novel cooling fan applied on notebook computers, which is consisted of an axial-flow impeller and a centrifugal housing. First of all, a basic axial-flow rotor is designed with the NACA airfoil; then, the prototype can be made by CNC machine and tested to serve as reference for further modification. All experiments regarding performance and noise characteristics in this analysis are executed in AMCA 210-85 chamber and semi-anechoic chamber. Thereafter, a parametric study on the geometry of fan is performed to enhance the understanding of the influences caused by those variations. The parameters considered here include impeller diameter, cut-off and tip clearances between casing and impeller, modifications of casing, and fan inlet-area. Experimental results show that blade designed with NACA airfoil enhances performance and reduce noise outcome. Decreasing the cut-off and tip clearances by increasing the rotor diameter demonstrates significant improvements on volume flow rate and static pressure. Besides, adding a second flow-channel between housing and rotor back-plate results in a dramatic increment on volume flow rate by the amount of 33.96﹪. Meanwhile, a 8.96﹪growth on volume flow rate is observed from the experiment on drilling holes in casing. Furthermore, under the same noise generation, variation of inlet area shows an impressive static pressure gain （88.18﹪） and moderate volume flow rate increment （9.91﹪）. Moreover, an extensive discussion for the influences on above parameters is provided.
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