Condensation on Highly Superheated Surfaces : Unstable Thin Films in a Wickless Heat Pipe

A wickless heat pipe was operated on the International Space Station to provide a better understanding of how the microgravity environment might alter the physical and interfacial forces driving evaporation and condensation. Traditional heat pipes are divided into three zones: evaporation at the heated end, condensation at the cooled end, and intermediate or adiabatic in between. The microgravity experiments reported herein show that the situation may be dramatically more complicated. Beyond a threshold heat input, there was a transition from evaporation at the heated end to large-scale condensation, even as surface temperatures exceeded the boiling point by 160 K. The hotter the surface, the more vapor was condensed onto it. The condensation process at the heated end is initiated by thickness and temperature disturbances in the thin liquid film that wet the solid surface. Those disturbances effectively leave the vapor "superheated" in that region. Condensation is amplified and sustained by the high Marangoni stresses that exist near the heater and that drive liquid to cooler regions of the device.

Medienart:

E-Artikel

Erscheinungsjahr:

2017

Erschienen:

2017

Enthalten in:

Zur Gesamtaufnahme - volume:118

Enthalten in:

Physical review letters - 118(2017), 9 vom: 03. März, Seite 094501

Sprache:

Englisch

Beteiligte Personen:

Kundan, Akshay [VerfasserIn]
Nguyen, Thao T T [VerfasserIn]
Plawsky, Joel L [VerfasserIn]
Wayner, Peter C [VerfasserIn]
Chao, David F [VerfasserIn]
Sicker, Ronald J [VerfasserIn]

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Volltext

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Journal Article

Anmerkungen:

Date Completed 05.02.2018

Date Revised 05.02.2018

published: Print-Electronic

Citation Status PubMed-not-MEDLINE

doi:

10.1103/PhysRevLett.118.094501

funding:

Förderinstitution / Projekttitel:

PPN (Katalog-ID):

NLM269961275