Abo Bibliothek: Guest

ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

NUMERICAL STUDY OF FLOW CHARACTERISTICS AND TEMPERATURE DISTRIBUTION OF FALLING FILMS OVER HORIZONTAL TUBES FOR SUPER-HYDOPHILIC SURFACE

Get access (open in a dialog) DOI: 10.1615/IHTC16.bae.023396
pages 1363-1378

Abstrakt

Falling film on horizontal tube banks is widely used in heat transfer exchanger, because it leads to a higher heat transfer performance. The behavior of falling film over horizontal is critical to the heat and mass transfer performance, especially at low spray density. In this paper, transient and steady variation characteristic of film flow process and temperature distribution over horizontal round tube on superhydrophilic surface were systemic investigated by CFD simulation. The two flow basic models, droplet and jet, was established as increasing flow rate. Based on the simulations, the droplet mode demonstrated a transient film thickness distribution with the spreading of film, which greatly increased the wave intensity compared with the jet mode. Meanwhile, the film distribution nearly had no variation in the jet mode over time and lower stagnation zone showed the maximum thickness. The average film thickness increase with increase in film Reynolds number. In addition, both the droplet and jet mode presented a sharped temperature local temperature increment nearly the lower stagnation zone, which usually appeared on circumferential angle was 160°, due to vortex velocity distribution inside the liquid film and the increment of temperature of the zone is lower as the increased of flow rate.