Intensification of heat transfer in a downward liquid-film flow

Heat transfer in a film flow of the FC-72 dielectric liquid down a vertical surface with an embedded $150\times150$ mm heater is experimentally examined in the range of Reynolds numbers $\mathrm{Re}= 5-375$. A chart of liquid-film flow modes is constructed, and characteristic heat-transfer regions are identified. Data on the dependence of heater-wall temperature and local heat flux at the axis of symmetry of the heater on the longitudinal coordinate are obtained. Local and mean heat-transfer coefficients are calculated. It is shown that enhanced heat transfer is observed in the region where rivulets starts forming in the low-Reynolds-number liquid-film flow.