Minimum heat flux (MHF) behavior with different surface characteristics including structured surfaces and different surface energies

Abstract

In a series of quenching experiments with smooth/structure hydrophilic/hydrophobic surfaces, the effects of surface wettability and surface structures on the minimum heat flux (MHF) behavior are observed. For a hydrophilic structure surface, early transition from film boiling to transition boiling at the MHF point occurs at the highest temperature (324 °C) in this experimental study. A smooth hydrophilic surface has 274 °C as the MHF temperature while a hydrophobic smooth surface shows the MHF behavior at lower temperature (208.8 °C). In contrast, there is no observable film destabilization with an observable MHF behavior on a hydrophobic structured surface during the quenching process. The test results are described by considering liquid-solid intermittent contact with an oscillating film interface in this study. For the intermittent contact, an equilibrium condition is proposed to describe the boiling transition with surface characteristics.