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Numerical Heat Transfer, Part A: Applications
An International Journal of Computation and Methodology
Volume 79, 2021 - Issue 9
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Research Article

Analysis of the two-phase flow, heat transfer, and instability characteristics in a loop thermosyphon

, , , &
Pages 656-680 | Received 16 Nov 2020, Accepted 25 Jan 2021, Published online: 12 Feb 2021
 

Abstract

Numerical modeling based on volume of fluid (VOF) method is conducted and experimentally validated for the two-phase flow and heat transfer in a loop thermosyphon for wide filling ratios. The results show that, under the 87% filling ratio, the loop is dominated by bubbly flow and sub-cooled flow boiling, with sensible heat transfer enhanced by bubble pumping effect, which is beneficial for wobbling, tilting, and mobile applications to avoid evaporator dry-out. Under the 64% filling ratio, geyser boiling instability occurs. A train of bubble-liquid intermittently passes the loop summit under the collaboration of buoyancy, gravity, viscous, and surface tension forces, causing intense flow and temperature oscillations, enhancing both latent and sensible heat transfer. Under the 38% filling ratio, the characteristic flow patterns are churn flow, mist flow, and film condensing, leading to highly efficient latent heat transfer.

Disclosure statement

We wish to confirm that there are no known conflicts of interest associated with this publication and there has been no significant financial support for this work that could have influenced its outcome.

We confirm that the manuscript has been read and approved by all named authors and that there are no other persons who satisfied the criteria for authorship but are not listed. We further confirm that the order of authors listed in the manuscript has been approved by all of us.

We confirm that we have given due consideration to the protection of intellectual property associated with this work and that there are no impediments to publication, including the timing of publication, with respect to intellectual property. In so doing we confirm that we have followed the regulations of our institutions concerning intellectual property.

Additional information

Funding

This work was supported by the National Natural Science Foundation of China (NSFC) projects under Grant Nos. 52076206 and 51706226.

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