Fig. 4 Bilateral film flow. (a) The front side; (b) The reverse side; (c) Diagram of BFF.
Fig. 4 shows the flow pattern of BFF. The operating conditions areF s = 0.8 (m/s*(kg/m3)0.5),L W = 26 m3/(m2*h). As shown in Fig. 4a, the liquid phase flows to the upper edge of the blade unit under the guidance of the guide blade. Affected by gravity, the liquid slowly wets the surface of the blade unit under the guiding action and forms a thin and stable liquid film. Because of the liquid-phase surface tension, the sieve holes are covered with the liquid layer as well; however, with the combined effect of gravity and the driving force of the gas phase, the liquid film on the sieve hole will gradually sink and accumulate into small droplets. The film at the sieve hole will be broken by the airflow, creating a smaller gap. However, the kinetic energy factor is relatively small; thus, the gas cannot break the liquid layer. The droplets affected by the viscosity forces attach to the rear of the unit sieve edge and form a dispersed liquid film flowing down the back of the unit. At the same time, the sieve holes broken by the gas phase will be covered by the liquid film again, repeatedly.
3.1.1.2. CPF