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ISSN Online: 2379-1748

ISBN Flash Drive: 978-1-56700-469-4

ISBN Online: 978-1-56700-470-0

Second Thermal and Fluids Engineering Conference
April, 2-5, 2017, Las Vegas, NV, USA

EXPERIMENTAL INVESTIGATION OF SURFACE FLOWS AND HEAT TRANSFER INDUCED BY HEXAGONAL DROPLET IMPINGEMENT ARRAY

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DOI: 10.1615/TFEC2017.tpd.017511

Abstract

In this work, an experimental study of surface flows and heat transfer induced by hexagonal droplet train impingement arrays is presented. A high frequency piezo-electric droplet generator was designed and constructed, which is capable of producing six and seven identical droplet trains arranged in a hexagonal array. HFE-7100 was used as cooling liquid due to its low boiling point and dielectric properties, specifically tailored for electronics cooling applications. A translucent sapphire substrate coated with a thin layer of indium tin oxide (ITO) was used as flat heating element. The surface flows and heat transfer induced by the hexagonal droplet train impingement arrays were characterized using well-calibrated high speed optical imaging and infrared (IR) thermal imaging techniques. High-speed optical images show that a hexagonal impact crater was formed within the impingement zone. Heat transfer results show that, at fixed flow rate conditions, lower impact spacing leads to better heat transfer performance within the impingement zone. However, higher impact spacing leads to better heat transfer performance outside the impingement zone. In summary, results to date reveal that the combined effects of the droplet Weber numbers and impingement patterns are important in the study of dropletinduced surface heat transfer phenomena.