[DoctorPDV]

Hello.
It is required to solve the following problem. There is a reclaiming cartridge in which there is a filtering substance (on the basis of chemically connected oxygen). The filtering substance looks like granules of the spherical form in diameter about 1 mm. The cartridge represents isolating protection frame of breath, i.e. the principle of its action is based on isolation of respiratory organs of the person from an environment and maintenance with air for breath from a source of a respiratory mix. Air for breath turns out from carbonic gas which is exhaled by the person. At passage СО2 through filtering substance (oxygen-containing product on the basis of super oxides of alkaline metals) occurs linkage of carbonic gas and allocation of oxygen necessary for breath


4КО2 + 2Н2О = 4КОН + 3О2 + 78 Kilojoule,

2КОН + СО2 = К2СО3 + Н2О + 141 Kilojoule.


I.e. at cartridge work the oxygen intended for breath is formed. Apparently from the equations of reactions, they pass about warmth allocation. In the course of work because of allocated warmth probably sintering of granules of filtering substance therefore cartridge service life decreases.
It is necessary to simulate work of a reclaiming cartridge, i.e. process of absorption of carbonic gas and oxygen allocation, thus to consider influence of allocated heat on absorbing ability of granules. Also it is necessary to trace a chemical compound of received air to define the moment when has begun проскок molecules СО2 through an absorber, in other words, when the absorbing substance is already incapable to transform all carbonic gas into oxygen. Also it is necessary to trace process of increase of concentration СО2 in air.
In connection with the given problem there is a question, what software product is necessary for using for its decision? (I tend Ansys CFX, but I am not assured). And whether there is any literature how to solve similar problems in the concrete program?
Thanks for the help.

[ghorrocks]

Hi,

CFX can model chemistry in the fluid but has more limited options when it comes to chemistry in granules. You can model lagrangian particles with chemistry (the coal combustion stuff in CFX is based around this), but it is not easy to get lagrangian particles to form a packed bed. Particle packing in CFX is done in fluidised bed combustors via a eularian approach. I don't know if this approach will work for you.

Alternately you could link CFX with a discrete dynamics software like EDEM (http://www.dem-solutions.com/). Then CFX can handle the fluid flow and EDEM can handle the particles, packing. This is a much more advanced approach but it will also require a lot more setting up and validation to get right.

It is not a simple problem you describe, it is going to take some work before you get useable results no matter what approach you take. I hope you are prepared for some advanced CFD!

Glenn Horrocks

[DoctorPDV]

Thanks for the answer!
Can you know any lessons (tutorial, video lessons) on chemical reactions in ANSYS CFX where processes pass with warmth allocation, that on the basis of these lessons (tutorial) I have tried to solve the given problem.
Thanks for the help.