An Experimental Study of Liquid Flooding in Vertical Large Scale Rectangular Channel With the Counter-Current Flow of Air and Water Film

Abstract

In the present study, a test facility, called WAFT [1], has been set up to study liquid flooding phenomena on a heated large flat plate with the counter-current air-water flow. The various thermal hydraulic working condition parameters, especially, temperature and velocity of water, air and oil media, could be obtained by adjust the control devices, such as, heater, valve and frequency regulator. Because of transparent organic glass slab in the test section, the dynamic behavior of water film flow in the different locations of test area can be clearly observed by virtue of high-speed video camera, such as wave pattern change, film rupture, droplet splash and dry spot occurrence. During the test, a series of tests were performed under the conditions of steel plate heat flux 25 kw/m2, the water film with mass flow rate 0.1 and 0.6 kg/s.m and the temperature 70 and 92 °C, the velocity of air entrance ranging from 6.0 to 11.50 m/s and the inlet air temperature of 45 and 60 °C, respectively. According to the acquisition data, a modified Wallis liquid flooding predicted relation was proposed considering the influence factor of temperature from large steel plates, air and water film, i.e., the effect of water film evaporation. The results indicate that the mass flow rate of water film and inlet air velocity have a great effect on the emergence of liquid flooding.