碩士 / 國立臺灣大學 / 機械工程學研究所 / 99 / Previous studies show that the lighting quality of LED largely depends on operating temperature. LED devices without thermal management may fail early due to thermal runaway, epoxy degradation, and thermal stress under high-operating temperatures. Piezoelectric fans have emerged as a viable cooling technology for the thermal management of low power electronic devices, owing to their low power consumption, minimal noise emission, and small and configurable dimensions. Previous study also shows the temperature of the heat source may reduce from 70.6℃to 37.4℃ by a piezoelectric fan in the case of heat plate.
The performances of the piezoelectric fans depend on amplitude of piezoelectric fan, vibration frequency, the direction of gravity, and relative position between heat source and piezoelectric fan. The heat transfer performance for horizontal location arrangement shows best performance at Xpzt/Lfin = 0.6. Based on the dimensionless analysis to the experimental results, the relationship with Repzt and Nupzt is linear when Repzt < 700. It’s is observed that the parameter γ=Gr/Repzt represents the importance of natural convection relative to forced convection. When γ < 1, natural convection is negligible. When γ > 10, forced convection is negligible.
| Identifer | oai:union.ndltd.org:TW/099NTU05489025 |
| Date | January 2011 |
| Creators | Wei-Han Ho, 何為瀚 |
| Contributors | Hsiao-Kang Ma, 馬小康 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 78 |
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