Maximum Heat Fluxes for Pool Boiling on Partly Ill-Wettable Heating Surfaces : (Part 2, Mainly on the Nucleate Boiling Having Tolerably High Superheat)

Abstract

Some experimental studies for examining the maximum heat fluxes in pool boiling of saturated water on partly ill-wettable heating surface are continued. Ill-wettable parts are realized by putting thin layers of silastic adhesive. In the previous report, experiments were carried out varying the width of such a region but in this report the test section has two parallel ill-wettable parts and the distance between these two parts is varied in order to examine their interference. In this case as the heat removal rates change locally, there exists a considerable temperature distribution along the heating surface. Especially in the normal part between two ill-wettable regions nucleate boiling having tolerably high superheat occurs. Such a boiling is examined by measuring the surface temperature, heat transfer coefficient and average void fraction.