EXPERIMENTAL STUDY OF HEAT TRANSFER AND HYDRODYNAMICS OF FALLING FILM ON A NOVEL DESIGN OF HELICAL FINNED TUBE EVAPORATORS

M. EL Haimer, A. Irhzo, M. Faraji, M. Nejam, F. Berroug

Abstract: An improved evaporator with helical finned tube falling film is presented. Its technology of building is simple and it is a question of piling plates in two wings, identical and simple forms, by respecting a regular gap between them to get the densely populated double helical finned tube of walk of staircase. This new evaporator design introduces advantages to have two helical fins taken up in parallel allowing doubling its area of exchange, a helical geometry allowing influencing flow favorably for a good distribution of the film and a strong density of walk of staircase playing promoters turbulence role that can improve its heat transfer coefficient side film. Thermal study, in heating, evaporating and convective boiling regimes, allowed showing, on the basis of the criterion of the thermal height unit, HTU, a better performance compared with mono-finned evaporators and the smooth double helical finned tube without walk of staircase of the same density.

Keywords: helical evaporator, falling film, double fins, density of walk of staircase, HTU

DOI: https://doi.org/10.15623/ijret.2016.0501046