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Lagrangian simulation

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Old   March 12, 2018, 10:01
Default Lagrangian simulation
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Hi All

Has anyone here worked with Lagrangian spray simulation. ? I have a doubt regarding the injector position in a nozzle.

I have a flat spray nozzle which produces droplets and the outlet of the spray is having some shape and I am not sure how can i simulate this in lagrangian method to see the droplet formation and its size. Kindly have a look on the image and let me know if there is any possibility to do this.

Thanks in advance.
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Old   March 13, 2018, 00:51
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Ashok Chaudhari
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Quote:
Originally Posted by AS_Aero View Post
Hi All

Has anyone here worked with Lagrangian spray simulation. ? I have a doubt regarding the injector position in a nozzle.

I have a flat spray nozzle which produces droplets and the outlet of the spray is having some shape and I am not sure how can i simulate this in Lagrangian method to see the droplet formation and its size. Kindly have a look on the image and let me know if there is any possibility to do this.

Thanks in advance.
I did some work in spray painting. Are you also trying to simulate atomization ?
Because atomization does it more tricky. Other things like injector position, type of injectors and injector angles etc., we can deal with. But for the atomization part we used a table to specify velocity, position vector and sizes. If you are able to validate any a atomization model first then other things are not that hard.
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Old   March 13, 2018, 20:20
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Steve
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Hello..

To tell you the truth.. I don't recommand to use spray simulation with star-ccm+..

Anyway, as ashokac7 said you should think about atomization.

if spray velocity is fast (high weber number), you can validate break up tuning constants. But if your item has low spray velocity (low weber number, no break up or less break up), you have to test for using particle distribution and use RR curve..

I think these are important. (except clear condition)

1. Spray angle
2. Initial Particle size (related effective area)
3. Particle distribution. (example : RR curve..)
4. Injection rate

Please keep in mind, spray simulation is not simple.
You have to validate not only SMD, but also penetraion length..

In any case, test results are required..
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Old   March 14, 2018, 07:28
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Dear Steve Lee

Yes you are true, sprays and atomization with lagrangian is really hard.
And regarding the weber number can we calculate from the free stream velocity or how is it ?
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