| Summary: | 碩士 === 國立交通大學 === 機械工程系所 === 107 === This study experimentally investigates the condensation performance of the HFE-7100 within a multiport micro-channel heat sink with a hydraulic diameter of 1200 μm. The experiment is conducted at a fixed outlet pressure of 140 kPa with condensation heat flux of 120W. The condensation tests are carried out with mass fluxes ranging from 150 to 250 kg/m^2 s, vapor mass quality from 0.1 to 0.8 and inclined arrangement from -90° (vertical downward) to 90° (vertical upward). In addition, the present study proposes enhanced condensation design via a micro-drainage cavity sitting in the middle of the conventional microchannel. Through this design, the condensate drainage is improved and condensation heat transfer is improved with additional benefit of lower pressure drop. The results show that the micro-channel heat sink with drainage channels is especially effective at lower mass flux like 100 kg/m^2 s, yielding 17% augmentation in heat transfer coefficient and a reduction of frictional pressure gradient by 30%. Similar results prevail when the mass flux is 150 kg/m^2 s, and 20% improvement of heat transfer coefficient and 25% lower pressure gradient can be achieved. However, the design offers negligible improvements with higher mass flux higher than 200 kg/m^2 s. This is because flow inertia takes control, and the effect of surface drainage is significantly impaired.
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