Boiling is a process in which phase change occurs from a liquid to a gaseous
aggregate state. Due to phase changes, a large amount of heat is transferred at small
temperature differences between the heating surface and the liquid. Pool boiling is one of
the most efficient methods of heat transfer, but we want to improve it due to the range of
different applications. One way to improve heat transfer in boiling is to use ultrasonic
waves. During boiling, the heating surface is covered with the vapor phase and the
transfer of heat is reduced, as the vapor acts as an insulator. The ultrasonic waves
accelerate the departure of the bubbles from the heating surface and in this way prevent
the bubbles to merge and form a vapor film. With the help of a high-speed camera, we
visualized the boiling process without the presence of ultrasound and at different
sonotrode amplitudes. The boiling process was recorded at different heat fluxes and
consequently in different boiling regimes. The experiment showed the positive influence
of ultrasound on the removal of vapor bubbles from the heating surface. The influence of
ultrasound is greatest at lower heat fluxes and decreases as the heat flux increases.
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