Role of extended surfaces on the enhancement of quenching performance

Abstract

High heat transfer rate is essential in several industrial applications, including, nuclear reactors, storage and transport of cryogenic liquid, and metal forming, which deal with the rapid cooling of various materials. Rapid cooling of surfaces at temperatures significantly higher than the boiling point of the coolant is often restricted by formation of a vapor layer around the surface that retards the rate at which heat can be dissipated. In the present work we report on the effect of finned structures of millimetric length scale on the enhancement of heat transfer performance during quenching. The fins are observed to destabilize hydrodynamic vapor layer during film boiling. We show that the quench duration reduces by ~3.8 times and the maximum heat flux (MHF) increases by nearly 230% for the finned sample as compared to the smooth samples. The quench duration and heat transfer rate are shown to be dependent on spacing between fins and the optimum fin spacing is determined to yield the highest MHF and minimum quench time.