Suppression of the Leidenfrost Phenomenon by Superhydrophilic Graphene Nanobush

Abstract

The Leidenfrost phenomenon considerably reduces the heat transfer at high temperatures, but proper micro/nanofabrication can enhance the heat transfer by elevating the Leidenfrost temperature. However, the complicated micro/nanofabrication techniques are difficult to implement in large-scale commercial applications. This paper describes superhydrophilic graphene nanobush (SGNB) on Cu plates prepared by the PECVD method and subsequent air plasma etching that improves the spray cooling heat transfer. The results show that the Leidenfrost temperature of SGNB/Cu plate is up to 240 °C greater than that of a bare Cu surface. The much higher temperature on the SGNB/Cu surface is due to the fast water wicking and spreading by the nanobush superhydrophilicity, as well as increased heat transfer area, increased number of boiling nucleation sites and the robust vapor channels provided by the porous nanobush structure. This study shows the great ability of the nanobush for enhancing the boiling heat transfer and a feasible strategy for suppressing the Leidenfrost phenomenon.