Enhancement of subcooled flow boiling critical heat flux for water in tubes with internal twisted tapes under one-sided-heating conditions

The heat flux distributions, qw, at the inner cooled wall for the beam irradiated test data using swirl tubes were estimated by solving an unsteady heat conduction equation. The results were compared with the net vapor generation heat flux, qNVG. It was confirmed that the lowest heat flux at the cooled wall was lower than qNVG for all data and this fact might enhance the critical heat flux (CHF) under non-uniform heating conditions. Enhancement of the CHF for the beam irradiated test data was closely connected with the region at qW>qNVG and the CHF multiplier could be related to the non-uniformity factor.