The effects of gap size, heat flux and inlet subcooling on the boiling incipience, flow pattern, heat transfer coefficient, flow instability and critical heat flux were analyzed and discussed.

Empirical formulae for the critical heat flux of the film breakdown and heat transfer correlations for normal and subnormal films are obtained by fitting the test data.

The world vertical upward flow round critical heat flux experimental database is analyzed based on the slice method, similarity measure, heat balance and inlet temperature verification.