The role of enhanced coated surface in pool boiling CHF in FC-72

The purpose of Critical heat flux (CHF) experiments was to determine the role of various types and thickness of enhanced coated surface on a horizontal, vertically oriented ribbon heaters made of Ti and Steel 1010 of different thickness. Saturated pool boiling in FC-72 at atmospheric pressure was used in the experiment. The microstructure and surface topography are important factors in pool boiling CHF. In conditions of highly wetting FC-72 and increased roughness, CHF increased by 6 to 12%. However, CHF increased by 29% with greater topographic unevenness of the surface and lower roughness, which was obtained by etching Steel 1010 in H2SO4 acid. CHF also increased when the content of metals and metal oxides particles in the coating were increased. The CHF ratio of enhanced coated surface to a ribbon heater featuring a standard surface finish is up to 2.3. In addition, the asymptotic CHF of these uncoated heaters was considerably exceeded.