The nucleate pool boiling heat transfer characteristics of smooth metallic surfaces were investigated using two highly wetting fluids. Perfluoro-n-hexane and n-hexane were chosen as the test fluids. Two single crystal metal surfaces (Copper and Aluminum) of two different crystal plane orientations in addition to two polycrystalline metal surfaces (Nickel and Titanium) were studied. Three different orientations of a non-metal surface (Silicon) were also studied. Heat transfer is seen to increase with increasing thermal conductivity for both single crystal and polycrystalline surfaces. For the single crystal metal surfaces, heat transfer slightly increases with decreasing planar density. For the silicon surfaces heat transfer increases with increasing planar density. Film boiling at incipience was observed for some of the surfaces. A plausible criterion for predicting the onset of film boiling at incipience is discussed.
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