Extending the limit of phase change heat transfer with piranha pin-fins for ultra-high heat flux dissipation
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Authors
Woodcock, Corey
Issue Date
2017-08
Type
Electronic thesis
Thesis
Thesis
Language
ENG
Keywords
Mechanical engineering
Alternative Title
Abstract
The Piranha Pin Fin (PPF) microstructure has been invented to augment CHF by venting the working fluid from the high-heat flux surface, which is replenished by highly subcooled fluid. Experiments have been performed on the silicon-based PPF heat sink at microgap mass fluxes ranging from 500 – 3700 kg/s/m² under system pressures of 1.4 and 2.8 atm. Heat transfer coefficients up to 75 kW/m²/°C were reported to mitigate chip heat fluxes up to 700 W/cm² using dielectric fluid HFE7000. Analysis of high speed camera microscope images showed that CHF in the PPF system begins with a vapor phase instability as vapors expand and coalesce in an unconfined area of the heat sink. The CHF condition was observed to be temporally dependent on the equilibrium quality of the fluid at the inlet, as well as the mass flux through the heat sink. Results from the first generation heat sink were used to optimize the PPF microstructure, as well as the overall heat sink geometry.
Description
August 2017
School of Engineering
School of Engineering
Full Citation
Publisher
Rensselaer Polytechnic Institute, Troy, NY