Electrohydrodynamic enhancement of pool boiling heat transfer on micro-column surfaces: Advantages and disadvantages

Abstract

The influences of electrohydrodynamics on enhanced boiling heat transfer performance under different sizes of micro-columns were explored. The results indicate that the electrohydrodynamic enhancement in the critical heat flux (CHF) of micro-column surfaces decreases as the micro-column spacing increases. Specifically, when the micro-column's width and spacing are both 30 μm, the CHF in HFE7100 exhibits enhancements of 66.4%, 31.5%, and 28.6% at ΔTsub = 3, 20, and 30 K, respectively. The field trap effect was more pronounced on the surfaces with larger micro-column spacing and at high liquid subcoolings. The PF90–90 in ES500 exhibited CHF decreases of 8.6% and 5.3% with the electric field under the subcoolings of 20 K and 30 K, respectively. Bubble behavior shows that the electric field has an advantage in increasing the liquid-vapor instability (far-field boiling heat transfer performance). However, the electric field has disadvantages in promoting the detachment of bubbles generated in the microchannels (near-field boiling heat transfer performance). Thus, the electrohydrodynamic enhancement of boiling heat transfer is weakened. These findings indicate that a synergistic enhancement of both near-field and far-field boiling heat transfer performance is necessary for further boiling heat transfer performance improvement.