ISSN Online: 2379-1748
ISBN Flash Drive: 978-1-56700-469-4
ISBN Online: 978-1-56700-470-0
Second Thermal and Fluids Engineering Conference
ELECTROWETTING-BASED ACCELERATED COOLING DURING QUENCHING
摘要
Boiling heat transfer at ultrahigh temperatures is drastically reduced by the formation of an insulating vapor layer above the surface. Electrowetting (EW) can suppress the formation of this vapor layer, and has been demonstrated to work for many fluids including water and organic solvents (isopropanol, methanol etc.). This work measures the heat transfer enhancement during quenching of metals, resulting from the application of EW voltages. The fluid-surface interactions and boiling patterns in the presence of an electrical voltage are imaged and analyzed. EW replaces film boiling with periodic wetting-rewetting cycles, and thus fundamentally changes the mode of heat transfer. The increased wettability substantially reduces the cool down time. The cooling rate can by increased by upto 3X. The results show that electric fields can dynamically tune the classical quenching curve. Overall, this study opens up new possibilities to control the metallurgy of metals via electrical control of the cooling rate.