| |
Fluent Inc. has initiated a collaboration with the Chemical Reaction
Engineering Laboratory (CREL) at Washington University in St. Louis to
develop a better understanding of the physics of bubble column reactors
(BCRs). Under the leadership of Prof. Milorad P. Dudukovic, CREL has emerged
as the premier US laboratory for studying gas-liquid flows and reactions
encountered in BCRs. The CREL program includes an emphasis on quantifying
flow, mixing, and reaction in multiphase reactors. Using unique instrumentation,
the laboratory is able to measure and report instantaneous velocities,
turbulence and back-mixing parameters, time-averaged flow patterns, and
complete voidage (gas holdup) distribution in gas-liquid, liquid-solid,
gas-solid, and gas-liquid-solid systems.
"With the advanced new features addressing gas-liquid flows in FLUENT,
we wanted to develop a validated modeling capability for bubble column
reactors", notes Fluent's Dr. S. Subbiah, Business Director for the US
Chemical Process Industry. "We saw CREL as the premier institution to
partner with in this regard. They have the infrastructure, as well as
a philosophy of doing fundamental research in line with vital industrial
interest." In February 1998, Fluent donated FLUENT software to CREL, and
has since worked with the researchers there to systematically develop
the best procedures to model gas holdup.
"FLUENT provides an easy-to-use CFD platform for testing the
validity of physical models, such as drag laws, against real data," says
Prof. Dudukovic. "As part of the partnership with Fluent Inc., my staff
was able to quickly learn the FLUENT software and provide meaningful results.
We intend to present our technical findings at the multiphase meeting
in Delft next year.
Professor Milorad P. Dudukovic,
Director of the Chemical Reaction Engineering Laboratory
(CREL) at Washington University
The collaborative project includes experimental observations of gas-liquid
dynamics and numerical simulations with FLUENT. The experiments involve
measurement of instantaneous velocity profiles of the liquid phase circulation
using Computer Automated Radioactive Particle Tracking (CARPT) and time-averaged
gas-holdup profiles using gamma-ray Computed Tomography (CT). From the
former technique, time-averaged and azimuthally averaged velocity profiles
are determined. Coupled with the gas holdup profiles obtained via tomography,
these measurements are being used for direct comparison with the FLUENT
results. The computations take only a few hours to run, using the new
coupled implicit (TDMA) solver that gives a significant speedup over earlier
versions of FLUENT.
The FLUENT results show an encouraging correlation
with observations of the bubble column reactor. Predictions show
gas holdup (top) and liquid velocity profile (bottom) at mid-height
in the reactor.
|
|
|
