Wind Turbine

chemical
The sparger assembly
For a recent project, several simulations of the reactor
were performed in an attempt to reduce the pressure
difference through the sparger holes that had caused
an overload problem on some of the compressors. In
order to accomplish the goal without any loss in productivity,
a decision was made to enlarge the sparger
hole sizes. Changing the sparger hole sizes had to be
carefully studied, however, because new problems might
be introduced in the process. Using FLUENT, several aspects
of the planned changes that would be critical to successfully
achieving the goal were checked. First, the flow
in the sparger itself was precisely investigated for various
hole sizes. The results were used to assess the distribution
of the gas flow rate per hole, and to test whether
the pressure difference for the gas exiting through the
holes was properly adjusted. Next, the liquid flow pattern
in the reactor was calculated. These results were
used to check for possible problems in the mixing patterns
in the vessel. As a result of this effort, it was found
that by modifying the agitator system, a better mixing
pattern could be achieved. The revised liquid solution
was then used as the basis for the gas sparging calculation,
which was performed using the discrete phase
model (DPM). This calculation was used to ensure that
the hole size proposed in the first phase of the project
would not lead to any unforeseen problems when the
sparger was activated. During this phase of the project,
the underlying assumptions for the DPM were validated,
and the fundamental concepts for bubble formation
by a gas emitted from a sparger hole in a liquid were
investigated.
As a result of the project work, the most appropriate
hole sizes for the spargers was chosen that would
satisfy the process goals while introducing no unexpected
problems in reactor operation. The results also helped
identify ways to modify other aspects of the agitating
system so that better gas dispersion could be obtained.
All of the ideas have since been applied in the field, and
the reactor is now operating successfully. ■
Path lines illustrate some of the bubble trajectories
The gas flow
in the sparger
Fluent NEWS spring 2002 11