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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-421-2

International Heat Transfer Conference 15
August, 10-15, 2014, Kyoto, Japan

Fabrication and Visualization of a Micro Pulsating Heat Pipe

Get access (open in a dialog) DOI: 10.1615/IHTC15.nms.009313
pages 5665-5676

Sinopsis

In order to investigate the effect of thermophysical properties of the working fluid on the thermal performance of the ????PHPs that had non-uniform channels, silicon-based micro pulsating heat pipes (????PHPs) were fabricated by MEMS fabrication process and tested at several input powers ranging from 6 W to 19 W. The ????PHPs exhibited an overall size of 35 mm × 40 mm × 1.25 mm and 64 parallel rectangular channels. Every two adjacent microchannels in the ????PHPs featured different width, 0.5 mm and 0.3 mm, and identical depth, 0.25 mm. The working fluid of the ????PHPs was either deionized water or methanol. The results showed that the ????PHPs charged with deionized water always failed to create the pulsating two-phase flow, regardless of the filling ratio and input power, and thus resulted in a higher thermal resistance, whereas the ????PHPs charged with methanol in a filling ratio of 80% were able to reveal the pulsating two-phase flow at an input power higher than 6 W. Because of the successful two-phase flow circulation inside the methanol-charged ????PHPs, the difference in thermal resistance between the methanol-charged ????PHPs and a solid “Silicon-Glass” sample of similar dimension increased as the input power increased. The failure in creating the pulsating two-phase flow in the water-charged ????PHPs is likely because the surface tension, latent heat of vaporization, specific heat and viscosity of water are so high that water is not favourable for the ????PHPs that had small channel size like the present one.