Characteristics of the high-temperature water film evaporation with countercurrent turbulent air flow in the duct

Highlights: • The falling water film evaporation mass transfer at high evaporation temperature along with the countercurrent turbulent airflow in a long duct was experimentally investigated, to simulate the passive containment heat removal characteristics of the Third Generation Nuclear Power Plant. • As the studies at falling water film evaporation at low evaporation temperature has been widely studied for kinds of industrial applications, the current work focused on the influence of the evaporation temperature on mass transfer, which is the main heat removal mode of the passive containment. • The experiments were performed under various conditions of the evaporation temperature and airflow velocities. • The experimental data were compared with previous results and correlations which were obtained or developed at relative low evaporation temperature. • Results showed that the evaporation temperature significantly contributes to evaporation mass transfer. • A modified correlation for falling water film evaporation at high evaporation temperature along with the countercurrent turbulent airflow was finally developed, as a function of the air Reynolds number, Schmidt number and advective mass transfer. • Besides, by comparison with the correlation by Kang and Park, it showed that their large prediction deviation at high temperature was due to the cubic power modification. • When the HMTA correlation by Huang and Yang is modified by the advective mass transfer, it could also predict the mass transfer very well at high evaporation temperature. - Abstract: Passive containment with high design pressure often has high evaporation temperature. The evaporation mass transfer with high evaporation temperature along with countercurrent turbulent airflow in a long duct was experimentally investigated. The experiments were performed for a wall surface temperature range of 71–90 °C. The experimental data showed that the high evaporation temperature significantly enhanced evaporation. By comparison, it reveals that the significant prediction deviation of the correlation from Kang and Park (Nuclear Engineering and Design, Vol. 204, pp 347–359, 2001) is mainly due to the cubic power modification. HMTA from Huang and Yang (Annals of Nuclear Energy, Vol. 76, pp 237–242, 2015) also underestimates the Sherwood number at high evaporation temperature but it could be applicable when the modification of the wavy interface and the advective mass transfer are included. A modified correlation for falling water film evaporation with high evaporation temperature is finally developed.