ABSTRACT
The gradually clarifying picture of the critical heat flux (CHF) is presented by explaining the outline of the CHF mechanism in fundamental boiling systems. First, the liberation from the long-lived restraint of the hydrodynamic instability CHF model is described. Then the CHF conditions in pool, external flow, and internal flow boiling are explained in a relatively unified manner as the limiting state of the macrolayer (or liquid sublayer) reducing the thickness or the mass flow rate with increasing heat flux, showing the need of the logically coordinative treatment of the Taylor and Helmholtz instabilities. Finally, considering the actual states on the heated surface near the CHF condition, the CHF is divided into two categories, i.e., the normal and the real CHF, and their relationship and characteristics are explained.
