Figure 3. A coupled thermal-hydraulic approach for modelling the boiling crisis.

The schematic shows a dry spot formed on the boiling surface underneath a mass of vapour at heat fluxes close to CHF. Substrate temperature at the centre of the dry spot should be higher because of lack of an effective heat removal mechanism. The boiling crisis phenomenon can be understood in terms of competition between liquid rewetting of the dry spot because of gravitational and capillary forces and enhanced liquid evaporation because of elevated surface temperatures in the interior of the dry spot.