Heat transfer enhancement due to interaction of the thermocapillary structures with waves on the surface of the heated liquid film

Characteristics of the film flow were determined experimentally using simultaneous measurements of the thickness and temperature fields on the surface of the falling heated liquid film (LIF and IR scanner). Three different types of instability were registered on the surface of the heated liquid film: 3D hydrodynamic and two thermocapillary A and B instabilities. The development of thermocapillary structures of type A was considered in the residual layer behind the front of the wave. These structures made a disturbance in the following wave front, leading to an increase in the amplitude of the waves. It was found that the amplitude of hydrodynamic waves in the upper part of the heater could be increased. The development of thermocapillary structures of type A at high heat flux initiated increasing of the rivulets deflection amplitudes. Heat transfer enhancement was registered with increasing amplitudes of wave and rivulets deflection.