Fig. 5 Continuous perforated flow. (a) The front side; (b) The reverse
side; (c) Diagram of CPF.
Fig.
5 shows the flow pattern of the CPF. The operating conditions areF s = 0.8
(m/s*(kg/m3)0.5),L W = 104
m3/(m2*h). As shown in Fig. 5a, the
liquid spray density is increased. The liquid film on the surface and
sieve holes of the blade unit is significantly thickened. With the
centripetal and centrifugal force at the internal and external blade
unit, the liquid film on the inside of the unit (near the inner
cylinder) and outside of the unit (near the outside cylinder) thickens
and is thin in the middle. On the reverse side of the unit, continuous
droplets and multiple streams flow through the sieve holes near the
inner cylinder because the slope is large on the inside. The downward
component of the velocity is increased. The liquid film thickens, and
the cumulative mass increases simultaneously, which increases the flow
velocity of the liquid film. The liquid cannot coat the sieve holes
under the influence of surface tension. The liquid phase flows through
the holes continuously. The slope of the middle and outer sides of the
unit is smaller than that of the internal unit, and the downward
component velocity is smaller. The flow rate of the liquid film
decreases, and the influence of the surface tension becomes significant.
The liquid film coats the sieve holes again and sinks and forms droplets
that adhere to the back of the blade unit, presenting a dispersed fluid
film flow. The flow mechanism is similar to that of the BFF.
3.1.1.3. DMF