Heat transfer from a small-size heater to a falling liquid film

Convective heat transfer from a heater with the height of 6.5 mm to a falling film of 25% mixture of ethyl alcohol in water is investigated experimentally. The Reynolds number varied in the experiments from 0.68 to 88.6. The heat flux density reached the value of 41 W/cm. As a result of the Marangoni effect, the modes of the steady formation of standing waves on the surface of the heater at Reynolds number varying from 0.68 to 9 were determined. The values of the heat transfer coefficient, from the heater to the liquid film obtained for two different regions of the heat flux density upon formation of large-scale structures. The results were generalized by empirical relations. The densities of the critical heat fluxes corresponding to the breakdown of the highly subcooled falling liquid film at Reynolds number from 0.68 to 9 are obtained.