3. Results and discussion
3.1. Flow patterns of the blade
unit
The flow pattern and transformation of that under two types of liquid
arrangement methods of the blade unit are discussed in this section. To
compare the results with similar research, the gas and liquid quantities
are characterized by the gas-phase
kinetic energy factor (F s) and the
liquid-phase spray density
(L W). The liquid film is evenly distributed on
the surface of the sieve plate unit under the overflow distribution;
therefore, the liquid spray density is the same as that under the spray
distribution. The kinetic energy factor of the gas phase and the spray
density are calculated as follows:
(1)
(2)
Here, u g represents the apparent velocity;L is the volume of the
liquid phase; A is the area
of the cross-section of the fluid, which equals πr2/4.
According to the experimental setup of Tang [25], the range of the
operating conditions is determined: gas-phase kinetic energy factor:F s: 0.4–4
(m/s*(kg/m3)0.5), gradient: 0.4
(m/s*(kg/m3)0.5); liquid spray
density: L W: 26–260
m3/(m2*h).
3.1.1. Flow patterns in overflow
distribution
The liquid phase is dyed with rhodamine B solution to observe the flow
patterns. Canon EOS 70D is used to take photos of the flow pattern. The
exposure time is 1/4000 s, and the ISO is 3200. An LED spotlight
(5MT-100W) is applied as a camera light source. Under the overflow
distribution, the flow patterns of the blade unit can be defined as
three types based on the characteristics of the rotational and
perforated flow of the gas-liquid two-phase flow system. They are
bilateral film flow (BFF), continuous perforated flow (CPF), and
dispersed-mixing flow (DMF) under the spray distribution, and film and
jet flow (FJF) and jet and mixed flow (JMF) under spray distribution.
3.1.1.1. BFF