EXPERIMENTAL STUDY OF HEAT TRANSFER IN BOILING OF VERTICAL FALLING FILMS

摘要

The boiling of falling films is a phenomenon in which three different mechanisms take place simultaneously: forced convection across the falling film, nucleate boiling on heated surface and evaporation at free surface of the film. The aim of the work is to obtain the heat transfer coefficient experimentally both for pure forced convection and for forced convection and nucleate boiling. Another aim is to obtain quantitative information about weight of forced convection in the total transferred heat flux. The experimental data were correlated by a dimensional equation, which expresses the heat transfer coefficient as a function of Reynolds number and transferred heat flux.