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Size Distribution Models - Spray Modelling

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Old   May 9, 2013, 23:13
Default Size Distribution Models - Spray Modelling
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Jack Lee
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Hi,

I am wondering if anyone can explain to me how does the size distribution models work and what kind of input I have to put it?

In spray modelling, instead of using Rosin-Rammler, how does one use distribution models such as fixed, general, etc etc which is located in /src/lagrangian/distributionModel

If not mistaken, I got a feeling that they are based on some Cumulative Distribution Function or some probability function. If anyone can refer to me what to look up for, I would also deeply appreciate it.

Thank you very much.
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Old   May 11, 2013, 06:35
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Hi,

with "general" you can give a volume probabilty for the droplet size in form of a table:

Quote:
sizeDistribution
{
type general;
generalDistribution
{
distribution
(
( 0.000075 2.752E-03 )
( 0.000125 1.000E-02 )
( 0.000175 1.331E-02 )
( 0.000225 1.642E-02 )
( 0.000275 2.058E-02 )
( 0.000325 2.535E-02 )
( 0.000375 3.005E-02 )
( 0.000425 3.416E-02 )
( 0.000475 3.737E-02 )
( 0.000525 3.967E-02 )
( 0.000575 4.104E-02 )
( 0.000625 4.166E-02 )
( 0.000675 4.157E-02 )
( 0.000725 4.100E-02 )
( 0.000775 3.990E-02 )
( 0.000825 3.866E-02 )
( 0.000875 3.699E-02 )
( 0.000925 3.531E-02 )
( 0.000975 3.358E-02 )
( 0.001025 3.160E-02 )
( 0.001075 2.979E-02 )
( 0.001125 2.800E-02 )
( 0.001175 2.616E-02 )
( 0.001225 2.441E-02 )
( 0.001275 2.276E-02 )
( 0.001325 2.119E-02 )
( 0.001375 1.968E-02 )
( 0.001425 1.825E-02 )
( 0.001475 1.691E-02 )
( 0.001525 1.565E-02 )
( 0.001575 1.449E-02 )
( 0.001625 1.342E-02 )
( 0.001675 1.239E-02 )
( 0.001725 1.142E-02 )
( 0.001775 1.052E-02 )
( 0.001825 9.688E-03 )
( 0.001875 9.023E-03 )
( 0.001925 8.307E-03 )
( 0.001975 7.638E-03 )
( 0.002025 7.016E-03 )
( 0.002075 6.440E-03 )
( 0.002125 5.912E-03 )
( 0.002175 5.551E-03 )
( 0.002225 5.116E-03 )
( 0.002275 4.700E-03 )
( 0.002325 4.312E-03 )
( 0.002375 3.954E-03 )
( 0.002425 3.625E-03 )
( 0.002475 3.324E-03 )
( 0.002525 3.153E-03 )
( 0.002575 2.937E-03 )
( 0.002625 2.706E-03 )
( 0.002675 2.490E-03 )
( 0.002725 2.291E-03 )
( 0.002775 2.108E-03 )
( 0.002825 1.940E-03 )
( 0.002875 1.789E-03 )

);

}
}
With "uniform" you define a constant droplet size for all your droplets.

Kind regards

Chrisi
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Old   June 11, 2013, 22:18
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HI. It took me awhile. but I figured that out already. Thank you very much anyway. By the way, do you have any idea of how to plot the velocity of the parcels/particles using paraview?

When I select a plane, and use "plot over a line", I cant obtain the velocities of the parcels. Is there anyway of easily measuring the velocity of the parcels?
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Old   June 1, 2016, 06:11
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Quote:
Originally Posted by Chrisi1984 View Post
Hi,

with "general" you can give a volume probabilty for the droplet size in form of a table:



With "uniform" you define a constant droplet size for all your droplets.

Kind regards

Chrisi

Dear Chrisi,
Is the second column indicating the cumulative distribution (Q3(xi)) ? And the first column diameter of the particle in meters?

Thanks for your help.
kind regards,
Alaska
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Old   June 8, 2016, 05:25
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Quote:
Originally Posted by Alaska1964 View Post
Dear Chrisi,
Is the second column indicating the cumulative distribution (Q3(xi)) ? And the first column diameter of the particle in meters?

Thanks for your help.
kind regards,
Alaska
Hey Alaska,
I have the same question? what does the second column mean?
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Old   June 8, 2016, 13:40
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Hey together,

the second colume should be ΔQ3(xi).

Kind regards
Chrisi
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Old   June 9, 2016, 09:14
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Thanks a lot Chrisi, I also think so since the summation of all data on second column is 1.

I have another question regarding the particle size distribution. Is there any model in OpenFOAM for log normal PSD?

there is a models for "normal" and "RosinRammler", but not for "lognormal". I have data with X50 X90 and geometrical size distribution (GSD). Do you have any idea how I can implement them to my spray model? I also have the data of ΔQ3(xi) for different intervals of diameter.

Cheers,
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Old   February 12, 2017, 01:18
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Hello Chrisi,

Can you please let me know what are the units of value 4e-03 in the following sizeDistribution model taken from bubbleCloudProperties file.

sizeDistribution
{
type fixedValue;
fixedValueDistribution
{
value 4e-03;
}
}

I am thinking that it is in meters. Am I right.

Please let me know.

Thanks & Regards,
Vidyadhar
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Old   March 26, 2018, 13:09
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Quote:
Originally Posted by Chrisi1984 View Post
Hey together,

the second colume should be ΔQ3(xi).

Kind regards
Chrisi

Hello Chrisi,

I have two questions about the sizeDistribution.

1. The second column of generalDistribution is the number/volume/mass fraction of that particular particle/droplet size, yes?
2. You said that "With "uniform" you define a constant droplet size for all your droplets". My question is we could use "uniform" to define a uniform distribution of droplet/particle size, yes?


Thanks and best regards,
Min
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Old   March 27, 2018, 16:14
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Quote:
Originally Posted by minzhang View Post
Hello Chrisi,

I have two questions about the sizeDistribution.

1. The second column of generalDistribution is the number/volume/mass fraction of that particular particle/droplet size, yes?
2. You said that "With "uniform" you define a constant droplet size for all your droplets". My question is we could use "uniform" to define a uniform distribution of droplet/particle size, yes?


Thanks and best regards,
Min
Hello together,

Regarding the questions:
1. The first column is the diameter in m. The second column is the volume probability for the corresponding diameter.
2. Yes

Kind regards
Chrisi
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Old   March 27, 2018, 16:28
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Quote:
Originally Posted by Chrisi1984 View Post
Hello together,

Regarding the questions:
1. The first column is the diameter in m. The second column is the volume probability for the corresponding diameter.
2. Yes

Kind regards
Chrisi


Hello Chrisi,

Thank you so much for your reply!

1. What do you mean by "volume probability", is it the same as "volume fraction"?
2. With "uniform size distribution", I mean it is a distribution between minValue and maxValue, instead of "a single particle size". So I am wondering what is your meaning, the former one or the latter?
3. I want to have three particle sizes and all three corresponding volume/number fractions are the same (equal to 1/3). So I am wondering which type of size distribution (general or uniform) could be used?

Thanks again for your kind help!

Best regards,
Min
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Old   March 30, 2018, 19:04
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Quote:
Originally Posted by minzhang View Post
Hello Chrisi,

Thank you so much for your reply!

1. What do you mean by "volume probability", is it the same as "volume fraction"?
2. With "uniform size distribution", I mean it is a distribution between minValue and maxValue, instead of "a single particle size". So I am wondering what is your meaning, the former one or the latter?
3. I want to have three particle sizes and all three corresponding volume/number fractions are the same (equal to 1/3). So I am wondering which type of size distribution (general or uniform) could be used?

Thanks again for your kind help!

Best regards,
Min




Corrections to Point 3:
3. I want to have three particle sizes and all three corresponding volume/mass fractions are the same (equal to 1/3). So I am wondering which type of size distribution (general or uniform) could be used?

My own understanding:
So I can use the "uniform" distributionModel. Because I need a uniform mass fraction and this is exactly what OpenFOAM "uniform" distributionModel gives.
Am I correct?
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Old   April 1, 2018, 14:52
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Quote:
Originally Posted by Azanulbizar View Post
HI. It took me awhile. but I figured that out already. Thank you very much anyway. By the way, do you have any idea of how to plot the velocity of the parcels/particles using paraview?

When I select a plane, and use "plot over a line", I cant obtain the velocities of the parcels. Is there anyway of easily measuring the velocity of the parcels?



Hello Azanulbizar,

I am wondering whether you could be so kind to have a look at my question.

size distribution models in OpenFOAM 4.x

Your help would be very appreciated!
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Old   May 25, 2021, 06:24
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Quote:
Originally Posted by minzhang View Post
Corrections to Point 3:
3. I want to have three particle sizes and all three corresponding volume/mass fractions are the same (equal to 1/3). So I am wondering which type of size distribution (general or uniform) could be used?

My own understanding:
So I can use the "uniform" distributionModel. Because I need a uniform mass fraction and this is exactly what OpenFOAM "uniform" distributionModel gives.
Am I correct?
I have the same question
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Old   May 26, 2021, 05:33
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I solved problem of having 2 sizes of particles by adding one more injection model with fixedValueDistribution. And it is possible to add as much as you want.


injectionModels
{
model1
{
type patchFlowRateInjection;
massTotal 1;
parcelBasisType mass;
massFlowRate 10;
patchName inlet;
duration 0.5;
concentration 2;
parcelConcentration 1e8;
SOI 0;
sizeDistribution
{
type fixedValue;
fixedValueDistribution
{
value 1e-6;
}
}
}
model2
{
type patchFlowRateInjection;
massTotal 1;
parcelBasisType mass;
massFlowRate 10;
patchName inlet;
duration 0.5;
concentration 2;
parcelConcentration 1e8;
SOI 0;
sizeDistribution
{
type fixedValue;
fixedValueDistribution
{
value 2e-6;
}
}
}
}
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Old   May 26, 2021, 08:27
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Hey Akimlav


I am struggling to understand the patchFlowRateInjection model, as there are not much written about it neither any tutorial available for that.



I saw that you used that model for your case, can you please explain the meaning of parameters required for the patchFlowRateInjectionModel, especially the keywords 'concentration' and 'parcelConcentration'?


Best Regards
Atul
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Old   May 26, 2021, 08:36
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Quote:
Originally Posted by atul1018 View Post
Hey Akimlav


I am struggling to understand the patchFlowRateInjection model, as there are not much written about it neither any tutorial available for that.



I saw that you used that model for your case, can you please explain the meaning of parameters required for the patchFlowRateInjectionModel, especially the keywords 'concentration' and 'parcelConcentration'?


Best Regards
Atul



Hi!


My knowledge is limited.



patchFlowRateInjection


Don`t know more than what here is said.


I played with the numbers in order to get amount of particles that I need.


Cheers!
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Old   June 1, 2021, 19:00
Default Size distribution model definition in openfoam8
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The following definition for the general distribution model is taken from openfoam8/src/lagrangian/distributionModels/general/general.H

Code:
Class
    Foam::distributionModels::general

Description
    A general distribution model where the distribution is specified as
    (point, value) pairs. By default the values are assumed to represent
    a probability density function, but the model also supports specifying a
    cumulative distribution function. In both cases it is assumed that the
    function is linear between the specified points.

    In both modes of operation the values are automatically normalized.

SourceFiles
    general.C
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Old   January 26, 2022, 12:32
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Does anybody know the formulation and mathematical background of the general distribution?? Any paper or somewhere to find??


btw check my new post!!
reactingFoam - Particle Size Distribution


thanks
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