Evaporation of a Combustible Liquid

[Kevin Taj]

I am trying to model the evaporation of a combustible liquid and
subsequent flow of fuel vapors throughout a space. I do not want
combustion, simply gas vapor flow. I have reviewed the ethanol
pan.fds example file and sections 8.3.2 and 8.3.3 (Liquid Fuels) of
the user’s guide. I am wondering if there is a way to turn off the
feature where the evaporated liquid (fuel gas) automatically starts
burning. Also, I need to be able to monitor the fuel gas quantity
with &SLCF PBY= …, QUANTITY='FUEL GAS’ /. I am running tests with the
ethanol pan example but would appreciate input from the group on how
to accomplish this if it is possible.

[drjfloyd]

You cannot turn off the combustion model. You can, however, change
the oxygen lower limit to prevent combustion from occurring. You will
need to decide for yourself if the evaporation model is providing you
with a reasonable evaporation rate.

[shostikk]

On top of what Jason wrote, I just add that the liquid evaporation
routine is currently tied up with the combustion model. This is
because the evaporation model compares the thermodynamic equilibrium
vapor pressure of the MATL to the concentration of gas phase fuel
inside the first grid cell above the surface. More generalized version
may be developed in the future, if we can get usefull results with the
liquid evaporation model. So, please tell us your findings!

Simo

[Kevin T]

I could change the oxygen lower limit to prevent combustion, however,
I don’t think I would be able to monitor the by-product (vapor) of the
reaction. I have found a way to do this by creating a species: SPEC
=’VAPOR’ and using NU_GAS (1, 1) = 1.0 in the MATL line for liquid
ethanol as outlined in section 11.2.3. I’m getting much too great an
evaporation rate, the gas appears to be lighter than air and I have
significant heating of the walls of the pan. I’m still testing the
input file.

On Sep 9, 5:13 am, shostikk <simo.hosti...@vtt.fi> wrote:
> On top of what Jason wrote, I just add that the liquidevaporation
> routine is currently tied up with the combustion model. This is

> because theevaporationmodel compares the thermodynamic equilibrium

> vapor pressure of the MATL to the concentration of gas phase fuel
> inside the first grid cell above the surface. More generalized version
> may be developed in the future, if we can get usefull results with the

> liquidevaporationmodel. So, please tell us your findings!

>
> Simo
>
> On Sep 8, 10:08 pm, drjfloyd <drjfl...@gmail.com> wrote:
>
>
>
> > You cannot turn off the combustion model.  You can, however, change
> > the oxygen lower limit to prevent combustion from occurring.  You will

> > need to decide for yourself if theevaporationmodel is providing you

> > with a reasonableevaporationrate.
>
> > On Sep 8, 3:01 pm, Kevin Taj <k.tajkow...@mcdowellowens.com> wrote:
>

> > > I am trying to model theevaporationof a combustible liquid and

> > > subsequent flow of fuel vapors throughout a space.  I do not want
> > > combustion, simply gas vapor flow.  I have reviewed the ethanol
> > > pan.fds example file and sections 8.3.2 and 8.3.3 (Liquid Fuels) of
> > > the user’s guide.  I am wondering if there is a way to turn off the
> > > feature where the evaporated liquid (fuel gas) automatically starts
> > > burning.  Also, I need to be able to monitor the fuel gas quantity
> > > with &SLCF PBY= …, QUANTITY='FUEL GAS’ /.  I am running tests with the
> > > ethanol pan example but would appreciate input from the group on how

> > > to accomplish this if it is possible.- Hide quoted text -
>
> - Show quoted text -