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Teaching Non-Ideal
Reactors with CFD Tools Luis M. Madeira, Manuel A. Alves and Alírio E. Rodrigues Departamento de Engenharia Química, Faculdade de Engenharia da
Universidade do Porto, Portugal |
This page complements a paper published in the Chemical Engineering
Education journal
(Vol.
38, pg. 154 –160, 2004)
If you have any problems seeing these
pages you can download them here
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Abstract: In this paper, a computational fluid dynamics
(CFD) code (Fluent) was used to illustrate important concepts regarding
residence time distribution (RTD) theory. The case-study adopted considers
isothermal laminar flow through 2-D reservoirs of different geometries
(various length/height, L/H, ratios), and a tracer step input
is simulated for RTD determination. From the steady-state solution,
quasi-stagnant zones are easily identified, particularly for high flow rates
(or, more rigorously, high Reynolds numbers) and for low L/H
ratios. In some cases, the fraction of dead volumes amounts to values as high
as 70%. For high L/H ratios one approaches the theoretical RTD
for laminar flow between parallel plates. Transient simulations are also very
useful because they allow 'visualization' of the evolution of tracer
concentration fronts, which animation is available in this web site. The RTD
obtained allows students to predict reactor's performance, either in
steady-state or transient regime. Such information can also be obtained
directly from Fluent by simulating the injection of a reactive feed stream.
The use of a commercially available CFD tool is illustrated to be
advantageous, as it allows students to easily 'visualize' and understand the
involved concepts, namely flow pattern and behavior/diagnosis
of non-ideal reactors. |
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Last updated:
02/02/2004 visits (since 02/02/2004)
mmalves <at> fe.up.pt