Influence of System Pressure on Pool Boiling Regimes on A Microstructured Surface Compared to A Smooth Surface

ABSTRACT

This study focuses on the influence of the system pressure on pool boiling regimes on a microstructured surface compared to a smooth surface. The microstructured surface consists of copper wires with diameters and lengths of 1 and 20 µm, respectively. The saturation pressure of FC-72 is varied between 0.5 and 1.8 bar. Boiling curves are determined and compared to those of a smooth copper surface. The results with the microstructured surface show no distinctive pressure dependency, contrary to those with a smooth surface being in good agreement with a state-of-the-art correlation. The microstructured surface exhibits higher heat transfer coefficients and lower critical heat fluxes than the smooth surface. The Nukiyama-curves of the microstructured and the smooth surface suggest the existence of distinctive sub-regimes of the isolated bubble regime: the partially activated isolated bubble regime and the fully activated isolated bubble regime.

KEYWORDS:

• Nucleate boiling
• microstructured surface
• pressure
• fc-72
• nanowires

Acknowledgments

We kindly acknowledge the financial support from the German Research Foundation (DFG) within the Collaborative Research Center 1194 “Interaction between Transport and Wetting Processes”, project C02 in collaboration with project A04. The authors would also like to acknowledge Marie-Theres Flietel and David Dexheimer for supporting the measurements and Florian Dassinger for the manufacturing of the microstructured surface.

Supplementary data

Supplemental data for this article can be accessed on the publisher’s website.

Nomenclature

p	=	pressure
pc	=	critical pressure
${\dot{q}}_{el}$	=	heat flux calculated using the supplied electrical power
r	=	ratio of the actual wetted surface to a smooth surface with the same dimensions
s	=	distance
Sa	=	arithmetical mean height of the surface
Sp	=	maximum height of peaks
Sv	=	maximum height of valleys
Tsat(p)	=	saturation temperature
Twall	=	wall temperature
Tw,meas	=	near-wall temperature

Greek Symbols

λCu

=

thermal conductivity of copper

Correction Statement

This article has been republished with minor changes. These changes do not impact the academic content of the article.

Additional information

Funding

This work was supported by the Deutsche Forschungsgemeinschaft