Measurement of evaporation heat transfer by falling film on horizontal tube having porous bodies

抄録

Falling film-type evaporators are expected to be an alternative to flooded-type evaporators to reduce the amount of refrigerant charging needed. The required conditions for falling film-type evaporators are a wet evaporator surface and higher heat transfer through liquid film.

In this study, the falling film heat transfer characteristics of R1233zd(E) on two horizontally installed porous body tubes of different thicknesses were experimentally investigated. The horizontal tubes were 19.05 mm in diameter and 400 mm in heat transfer length. The experiment covered heat fluxes from 3 to 40 kW m^–2 with several different amounts of liquid flowing down. The heat transfer coefficient of a tube with 1 mm porous bodies thickness was higher than that of a tube with 2 mm porous bodies thickness. Thus, the porous bodies had an appropriate thickness.