Saturation Boiling Critical Heat Flux of PF-5060 Dielectric Liquid on Microporous Copper Surfaces

Abstract

Pool boiling experiments are performed to investigate potential enhancement of critical heat flux (CHF) of PF-5060 dielectric liquid on microporous copper (MPC) surfaces and the effect of surface inclination angle. The morphology and microstructure of the MPC surfaces change with thickness. The experiments tested seven 10 Â 10 mm MPC surfaces with thicknesses from 80 to 230 lm at inclination angles of 0 deg (upward facing), 60 deg, 90 deg (vertical), 120 deg, 150 deg, 160 deg, 170 deg, and 180 deg (downward facing). CHF increases as the thickness of the surface increases and/or the inclination angle decreases. The values in the upward facing orientation are 36-59% higher than on smooth Cu. For all surfaces, CHF values in the downward facing orientation are approximately 28% of those in the upward facing orientation. A developed CHF correlation, similar to those of Zuber and Kutateladze, accounts for the effects of inclination angle and thickness of the MPC surfaces. It is in good agreement with experimental data to within 68%. Still photographs of nucleate boiling on the MPC surfaces at different inclinations help the interpretation of the experimental results.

Saturated pool boiling of FC-72 from enhanced surfaces produced by Selective Laser Melting

“…The increase in latent heat transfer mechanism (up to 10 times) was suggested as the main reason for the improved heat transfer recorded [10]. Similarly, El-Genk and Ali [11,12,13] employed the two-stage electrodeposition approach and produced microporous copper surfaces consisting of nanodendritic layers. Their experimental results showed that nucleate boiling heat transfer coefficient and CHF of 13.5 W/cm 2 K and 27.8 W/cm 2 could be achieved respectively with the microporous surface of 171 μm thickness [12].…”

Experimental Study on the Stability and Transient Behavior of a Closed-Loop Two-Phase Thermosyphon (CLTPT) Charged with NOVEC 649

“…However, the CHF point must never be overcome because, in that case, the system is displaced to a film boiling regime. Some authors, such as El Genk and Ali [35], recommend maintaining the maximum heat flux below 70% of the CHF. The nucleate boiling heat flux in a pool boiling system can be estimated through the classical Rohsenow's correlation shown in Equation ( 5) [18].…”