Synthetic view of the CHF mechanism in subcooled flow boiling based on the recent mechanistic models

Four mechanistic models of mutually somewhat different kinds published recently for the subcooled flow boiling critical heat flux (CHF), based on a common basic mechanism of liquid sublayer dryout, are reexamined synthetically with the following main results. First, for highly (or sufficiently) subcooled flow conditions, a detailed analysis of one of the foregoing models (i.e., Celata et. al. model) has revealed a possibility of the existence of a new CHF mechanism, which is surprising because of a different nature from the liquid sublayer dryout mechanism. Second, as for the region of low subcooled flow near the exit (equilibrium) quality of x(e) = 0, a possibility is suggested that rather complicated situation of CHF is observed particularly at low pressures, requiring further detailed studies in the future.