Abstract
Boiling heat transfer from a hydrophilic/hydrophobic combined surface is studied to examine effects of the size of PTFE (hydrophobic) circle dots on subcool boiling. In comparison with among different degree of subcooling, the degree of subcooling become smaller , the heat transfer enhanced and bubble nucleation starts earlier. Under the subcooled condition, as the size of PTFE dots become smaller, the heat transfer improved more after bubble nucleation starts. And, the domain of PTFE acts as nucleation sites. The bubbles stay on the dots area of PTFE coating without departing and the bubbles keep the hemispherical shape with oscillating up and down.
