hrr in pyrolysis

[gforney]

Please complete the following:

Application Version:FDS 6.0 beta
SVN Revision Number:6.0.11
Compile Date:

FDS can record the hrr of gas reaction.
But, exothermic pyrolysis process also have heat release.
If it is possible to improve the code to record this part of hrr?

Original issue reported on code.google.com by sv0908 on 2013-08-22 10:42:39

[gforney]

(No text was entered with this change)

Original issue reported on code.google.com by mcgratta on 2013-08-22 13:09:54

[gforney]

By definition, the HRR in FDS includes the gas phase heat release rate. 

The solid phase heat release due to the exothermic reactions is treated as a source
term in the solid phase heat conduction equation. If that should be included in HRR,
should the same be done for endothermic sources due to the heat of reaction?

I think the most usefull way of monitoring the heat release / consumption within the
solids would be to define a separate integral quantity that sums up the net source
terms within a solid. 

Original issue reported on code.google.com by shostikk on 2013-08-22 13:31:07

[gforney]

Actually, I want to build a model that a type of particles with pyrolysis reaction are
introduced into the space, and the reaction is exothermic. I want to see the contribution
of the reaction to the hrr. Do you have some advise?

Original issue reported on code.google.com by sv0908 on 2013-08-22 14:17:52

[gforney]

By the way, the pyrolysis reaction can be influenced by the local fraction of oxygen.
And if the code is developed to consider the consumption of oxygen in the pyrolysis
reaction? Whether the concentration of gas phase oxygen is reduced during the process?

Original issue reported on code.google.com by sv0908 on 2013-08-22 14:27:36

[gforney]

Simo -- does the special DSC output in FDS essentially do what he wants?

Original issue reported on code.google.com by mcgratta on 2013-08-22 16:53:54

[gforney]

Kevin - I'm afraid not. DSC output normalizes the convective heat flux by initial mass.
Here we would want to monitor the solid phase source terms. In DSC simulations, it
works because we turn off radiation and force the convection high. In real simulation
it would not work.

One way to calculate it would be to define a gas phase product for the reaction, and
monitor the overall production of that species. Clumsy, though.

The response to the oxygen consumption is in discussion thread 
https://groups.google.com/forum/?fromgroups#!topic/fds-smv/g9hQcSCjwfw

Original issue reported on code.google.com by shostikk on 2013-08-23 07:01:25

[gforney]

If it is easy enough to make this a solid phase quantity, let's do it. One can then
use STATISTICS to integrate over a particular surface. We can do this already with
generated species.

Original issue reported on code.google.com by mcgratta on 2013-08-23 12:02:01

[gforney]

We need two more scalar variables for each ONE_D array to store the endothermic and
exothermic source terms. (Better to store them separatelly.) These quantities need
to be integrated for each PYROLYSIS solve. 

Maybe put it all behind a flag that checks if the output is needed?

Original issue reported on code.google.com by shostikk on 2013-08-26 09:09:06

[gforney]

Has there been any more work on this issue?

Original issue reported on code.google.com by mcgratta on 2014-08-08 21:39:35

[gforney]

I'm afraid not. Should we close or keep open hoping that some day...

Original issue reported on code.google.com by shostikk on 2014-08-11 11:32:42

[gforney]

Closed

Original issue reported on code.google.com by mcgratta on 2015-03-09 18:07:56