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Effects of Heating Configuration and Operating Parameters on Heat Transfer and Interfacial Physics of Microgravity Flow Boiling With Subcooled Inlet Conditions –Experiments Onboard the International Space StationThis study is part of the Flow Boiling and Condensation Experiment (FBCE), a collaborative effort between the Purdue University Boiling and Two-Phase Flow Laboratory (PU-BTPFL) and the NASA Glenn Research Center. The FBCE fitted with the Flow Boiling Module (FBM) was launched to the International Space Station (ISS) in August 2021 and experiments were successfully performed from February to July 2022 to amass a large microgravity-flow-boiling database. This study is focused on heat transfer and flow visualization of microgravity flow boiling of n-Perfluorohexane in a rectangular channel of 5.0 mm height, 2.5 mm width (heated), and 114.6 mm length, with subcooled inlet conditions. High-speed-video photography is utilized to present flow patterns and temporal interfacial behavior. Heat transfer results are presented in the form of flow boiling curves and both parametric curves and streamwise profiles of wall temperature and heat transfer coefficient. Firstly, the parametric effects of mass velocity (199.4 – 3200.0 kg/m2s), inlet subcooling (0.2 – 46.0°C), and inlet pressure (124.2 – 176.7 kPa), on the aforementioned aspects are assessed for double-sided heating to establish them for a microgravity environment. Of these three parameters, mass velocity and inlet subcooling mostly determine the microgravity flow boiling behavior, while inlet pressure plays an insignificant role. Flow patterns for double-sided heating are more complex than those for single-sided heating due to interaction between the two vapor layers. Vapor interaction is minimized at high subcoolings and high mass velocities due to strong condensation offered by the subcooled bulk liquid layer separating them. Despite the different flow patterns, both single- and double-sided heating generally result in similar parametric trends and local heat transfer coefficients for similar operating conditions. Flow instabilities manifest as temporal flow anomalies and temperature oscillations, and their severity increases with increasing boiling number. Secondly, the effects of heating configuration are analyzed by comparing and contrasting several aspects of single- and double-sided heating data. The heat fluxes at which onset of nucleate boiling degradation (ONBD) and critical heat flux (CHF) occur are distinctly different for single- and double-sided heating. There exists a threshold inlet subcooling demarcating the dominance of flow acceleration and condensation effects in vapor removal from the near-wall region and replenishment of fresh liquid for boiling. Above the threshold, condensation from the near-wall region is dominant and single-sided heating yields higher heat fluxes, and below it, acceleration is dominant and double-sided yields higher heat fluxes. At mass velocity in the range of 200 – 2400 kg/m2s, the threshold inlet subcooling lies in the approximate range of 20 – 30°C (corresponding inlet quality of roughly -0.40 – -0.20).
Document ID
20230013643
Acquisition Source
Glenn Research Center
Document Type
Accepted Manuscript (Version with final changes)
Authors
Issam Mudawar
(Purdue University West Lafayette West Lafayette, Indiana, United States)
V.S. Devahdhanush
(Purdue University West Lafayette West Lafayette, Indiana, United States)
Steven J. Darges ORCID
(Purdue University West Lafayette West Lafayette, Indiana, United States)
Mohammad M. Hasan
(Glenn Research Center Cleveland, Ohio, United States)
Henry K. Nahra
(Glenn Research Center Cleveland, Ohio, United States)
R. Balasubramaniam
(Case Western Reserve University Cleveland, Ohio, United States)
Jeffrey R. Mackey
(HX5, LLC)
Date Acquired
September 20, 2023
Publication Date
September 28, 2023
Publication Information
Publication: International Journal of Heat and Mass Transfer
Publisher: Elsevier
Volume: 217
Issue Publication Date: December 15, 2023
ISSN: 0017-9310
e-ISSN: 1879-2189
Subject Category
Fluid Mechanics And Thermodynamics
Funding Number(s)
WBS: 619352.06.11.02.02.01
CONTRACT_GRANT: 80NSSC22K0328
Distribution Limits
Public
Copyright
Use by or on behalf of the US Gov. Permitted.
Technical Review
Single Expert
Keywords
Microgravity
flow boiling
liquid-vapor mixture inlet
flow patterns
high-density fronts
heating configuration
two-phase heat transfer coefficient
International Space Station
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