Abstract
The sound development of knowledge for generalized saturated and subcooled pool boiling CHF mechanisms and those correlations for test heater surface conditions in water and wetting liquid such as Fluorinert etc. are becoming increasingly important as the fundamental database for not only the design of high heat flux cooling system recently needed but also the derivation of subcooled flow boiling CHF correlations based on the pool boiling ones. Recently the saturated and subcooled pool boiling CHF for a horizontal cylinder in water and wetting liquids such as liquid nitrogen, liquid helium etc. were measured for comparatively wide ranges of pressure and subcooling. It was clarified that the CHFs measured were mainly divided into two groups for lower and higher subcooling at a pressure as a typical case. It was assumed that the former and latter CHFs occur due to hydrodynamic instability (HI) and explosive-like heterogeneous spontaneous nucleation (HSN) on the cylinder surface respectively. This paper suggests that more study on the effect of the cylinder surface condition on the transient CHF is necessary.
