| Summary: | 碩士 === 國立臺灣科技大學 === 機械工程系 === 94 === A streamlined heat sink assembly, which consists of the cooling fan and the streamlined fins, is designed simultaneously for meeting the thermal task of laptop computers in this research. At first, a systematic scheme including CFD simulation, mockup fabrication, and experimental verification, is established to generate a complex fan. This novel blower (60×60×15mm3), featured with the characteristics from both centrifugal fan and cross-flow fan, provides a sufficient airflow with high-pressure rise under the space limitation of notebooks. Moreover, a combined effort from numerical simulation and experimental verification is executed to perform the parametric study on the geometric variables for obtaining an optimum fan design. The parameters considered here include inlet diameter, shape of rear wall, tongue clearance, throat gap, and the height of rotor. In additions, prototypes are made by CNC machine and tested to serve as references for numerical verification. This parametric study indicates that increasing the rotor height is the key factor to enhance the fan aerodynamic performance. Also, experimental results verify that the optimum fan design operating at 3,000 rpm delivers 5.3-CFM airflow with 8.48mm-Aq static-pressure.
Thereafter, to match the flow pattern appropriately and minimize the resistance to the passing airflow, the streamlined fin geometry is generated with the aids of the detailed, numerical flow visualization at the fan outlet. Under the same operating conditions, experimental outcome shows that this strteamlined fin geometry yields a slightly better thermal resistance (1.154℃/W) compared to the traditional vertical fin (1.228℃/W), which represents a reduction of 2℃ on CPU case temperature. In conclusion, this new design approach, which generates the new cooling fan type and fin simultaneously, offers a reliable alternative to enhance the thermal performance of heat sink assembly successfully for meeting the thermal challenge of the high-performance notebooks.
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