Introduction Of all the modes of boiling, nucleate boiling is associated with the highest heat transfer coefficients. As a result, this process is of great interest with regard to applications as well as basic understanding. Numerous studies of nucleate boiling heat transfer have been reported in the literature. The results of these studies have generally been given in the form of correlations. So far, relatively few attempts have been made to describe the nucleate boiling process in a mechanistic way, and those efforts have met with little success. The primary cause for the very limited success of those attempts is a lack of understanding of the interaction of several surface and fluid parameters. To facilitate further development of mechanistic models of nucleate boiling and maximum heat fluxes, the purpose of the present work is to determine experimentally the interplay between the wall void fraction, surface wettability, and vapor flow dynamics away from the wall. The earliest correlation for nucleate boiling is that o
