Abstract
Experiments of pool saturated boiling of water were conducted using micro/nano hierarchical structured surfaces. We tried to make hierarchical structures without MEMS fabrication processes such as photolithography and dry etching, and in this study, the structured superhydrophilic surfaces were fabricated by two kinds of thermal spray method and chemical oxidation using an alkaline solution. The hierarchically structured surface fabricated by chemical oxidation of a plasma sprayed copper surface indicated the maximum critical heat flux of 1.8 MW/m^2 corresponding to 1.8 times the CHF of rough copper bare surface. Finally, the mechanism of CHF enhancement on superhydrophilic surface was discussed based on the water permeability in the micro and nano strucutures on the surfaces quantitatively evaluated by the capillary tube method.
