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shock tube with reaction
Posted 2011/03/21 14:30 GMT-4 Computational Fluid Dynamics (CFD), Chemical Reaction Engineering, Studies & Solvers Version 4.1, Version 4.2 2 Replies
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I'm new to comsol and I need some help figuring out if this is the right platform for the job.
I'll start a new project involving a shock tube. Some where in the tube a "curtain" of particles will be dropped by an automatic mechanism. The objective is to study the particles combustion reaction kinetics as the shock front passes through them, knowing that their displacement along the tube can be neglected. Is the Chemical Reaction Engineering Module suitable for this system?? Will I have the ability to control the time step and use very small increments (maybe 10^6s or less)??
Thanks.
Hello xpto56
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Since I have a dimerisation reaction and not a combustion for the moment, I added the reaction without using the "Chemical Reaction Engineering" interface.
Since I have high velocities, I use the new "High Mach Flow" module. It is quite ok, but I have the following problems:
- if I calculate just flux (meaning I do not couple concentrations), it has sometimes overprediction of velocities and temperature of the reflected wave;
- if I couple concentrations, there are a divergence problems. I was told the "High Mach Flow" is thought for a single ideal gas, so that's probably the cause;
- I was not able to get convergence with turbulence, with or without coupling of concentrations. So I am computing laminar flows.
So I would say that at the moment the "High Mach Flow" module ist not 100% suitable for reactions and it will probably not work for combustion.
If you made some positive experience, I could send you my e-mail address for sharing infos.
Bye,
Fabio
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I am trying something very similar.
Since I have a dimerisation reaction and not a combustion for the moment, I added the reaction without using the "Chemical Reaction Engineering" interface.
Since I have high velocities, I use the new "High Mach Flow" module. It is quite ok, but I have the following problems:
- if I calculate just flux (meaning I do not couple concentrations), it has sometimes overprediction of velocities and temperature of the reflected wave;
- if I couple concentrations, there are a divergence problems. I was told the "High Mach Flow" is thought for a single ideal gas, so that's probably the cause;
- I was not able to get convergence with turbulence, with or without coupling of concentrations. So I am computing laminar flows.
So I would say that at the moment the "High Mach Flow" module ist not 100% suitable for reactions and it will probably not work for combustion.
If you made some positive experience, I could send you my e-mail address for sharing infos.
Bye,
Fabio
Hi!!
Thanks for the ingo regarding the High Mach Flow module. I haven't tried it yet because I was using the basis of the shock-tube sample available in Comsol. However I'm dealing with some divergency issues. The most noteworthy happens when I increase de amplitude of the step function (the one used to define the initial conditions of the shock-tube - the discontinuity). Did you had this type of problems??
If I have any improvement on my model I'll let you know.
Thanks.
Pedro Santos