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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

EXPERIMENTAL STUDY OF SUBCOOLED FLOW BOILING HEAT TRANSFER ON MICRO-PIN-FINNED SURFACES IN SHORT-TERM MICROGRAVITY

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.024321
pages 1053-1060

Abstract

The flow boiling heat transfer of subcooled air-dissolved FC-72 on smooth surface and micro-pin-finned silicon chip (PF30-60) was studied in microgravity by utilizing the drop tower facility in Beijing. For comparison, experiments of flow boiling heat transfer in terrestrial gravity were also conducted. High-speed visualization was used to supplement trends observed in the heat transfer and vapor-liquid two-phase flow characteristics. The effects of inlet velocity, micro-pin-fins on flow boiling heat transfer as well as vapor-liquid two-phase flow were explored. Compared with the smooth chip, the CHF of PF30-60 is slightly higher than that of the smooth chip at the same inlet velocity. Gravity level affects flow boiling distinctly on PF30-60 compared with the smooth chip although PF30-60 has better heat transfer performance. The impact of gravity on flow boiling not only depends on the inlet liquid velocity, but also lies with the channel geometry parameter and surface conditions. Bubbly flow dominated the flow pattern during the nucleate flow boiling. Compared with the smooth chip, PF30-60 can maintain the stable bubbly flow at higher heat fluxes, and this tendency is more obvious as the inlet velocity increases. The micro-pin-fins and higher inlet velocity help for maintaining the stable bubbly flow, and also help for the steady nucleate flow boiling in microgravity.