Re: [sparta-users] [EXTERNAL] Validation chemical reactions in a box

[Marc V. M. <mar...@kr...>]

Dear Michael,

Thanks for the feedback. The comparison I'm trying to do is not only
against other codes but also analytical data. Therefore, I took the
reaction parameters described in sparta/examples/chem example which I
believe is a similar case. My next question would be where the Arrhenius
activation energy Ea, prefactor A, and exponent b, used in the example case
are obtained from. Is a general database stating these parameters for all
chemical reactions at different temperatures publicly available?

The next cases that I wanted to replicate are the validated test cases that
were used to validate SPARTA and presented in the slides from the short
course in 2015 available from the website. To better understand the
chemical reactions taking place on the surface and to have a reference, is
it possible to obtain the cases set up that were used for those
validations?  This would validate the chemical reactions on the surface
which requires some input data for the reactions that I'm
struggling to find. Do you know where I can find reliable data for the
reactions taking place on the surface?

Thanks in advance,
Marc

El jue, 12 sept 2024 a las 16:41, Gallis, Michael A. (<ma...@sa...>)
escribió:

> Marc
>
>
>
> This is a very interesting comparison you are trying to do. However,
> before you make a code-to-code comparison you need to make sure both codes
> are using the same molecular parameters, relaxation rates and most
> importantly reaction rates.
>
>
>
> Michael
>
>
>
> *From: *Marc Vives Massana <mar...@kr...>
> *Date: *Thursday, September 12, 2024 at 6:42 AM
> *To: *spa...@li... <
> spa...@li...>
> *Subject: *[EXTERNAL] [sparta-users] Validation chemical reactions in a
> box
>
> Some people who received this message don't often get email from
> mar...@kr.... Learn why this is important
> <https://aka.ms/LearnAboutSenderIdentification>
>
> Dear SPARTA users,
>
>
>
> I've been working on a validation case for the chemical reactions but the
> results are not as good as expected.
>
>
>
> The case is based on the work done by Scanlon et al. (see:
> https://doi.org/10.2514/1.J053370) who were validating dsmcFoam. The case
> basically consists of a box of side length 1e-5 m with gas at 20.000 K and
> 0.0063 atm. The boundaries are specular and adiabatic walls. Initially,
> there is only O2 present in the box and only the dissociation reactions are
> considered:
>
> O2 + O2 --> O + O + O2
> O2 + O --> O + O + O
>
>
>
> I tested the TCE and QK models and the results for the temperature and
> species fractions are not so good, see the figures below. Therefore, I
> kindly ask if someone could help me in implementing the chemical reactions
> or finding some validated cases with SPARTA so I could take a look at them.
>
>
>
> Thanks in advance,
>
> Marc Vives
>
>
>
> I'll also leave the input file in case it helps:
>
>
>
> ## INITIALISATION ##
>
> seed 12345
> dimension 3
>
> global gridcut 1e-5 comm/sort yes
>
> global mem/limit 1024
>
> units si
>
> boundary        r r r
>
>
> # PROBLEM DEFINITION ##
>
> variable l equal 1e-5/2
> create_box      -$l      $l       -$l      $l       -$l      $l
> create_grid     10 10 10       block * * *
>
> global          nrho 2.3118406573249943e+22 fnum 463
>
> species         air.species O2 O
> mixture         air O2 O vstream 0.0 0.0 0.0 temp 20000
> mixture         air O2 frac 1.0
> mixture         air O frac 0.0
>
> create_particles air n 0
>
> ## SETTINGS ##
>
> collide vss air air.vss
> react tce air.tce
>
> timestep        1e-9
>
> ## RUN ##
>
> compute counts count O2 O
> compute temp temp
> fix output print 1 "$(step) $(c_temp) $(c_counts[1]) $(c_counts[2])" file
> output screen no
>
> stats_style step np ncoll nreact c_temp
>
> stats 1000
>
> run 10000
>
>
>
>