Learning Forum

[RajasekarK123]

Why i am getting this error when using pressure swirl atomizer in a 2d axisymmetric problem?n

[Surya Deb]

Hello, nCheck your mass flow rate. It might be too low for instabilities to form and subsequent jet breakup. nTry to test it by increasing the flow rate.nRegards,nSDn

[Rob]

I modelled 2d axisymmetric model with Pressure swirl nozzle as an atomizer and i am getting this error, i am getting no convergence on mass evaporated, mass weighted average of species etc as in the figureshttps://us.v-cdn.net/6032193/uploads/VZFB2JF9SGHA/image.pnghttps://us.v-cdn.net/6032193/uploads/RC6NCVQN3ZYC/image.pnghttps://us.v-cdn.net/6032193/uploads/GPNZPJL37CN0/image.pnghttps://us.v-cdn.net/6032193/uploads/US3EDPW5AAX5/image.pnghttps://us.v-cdn.net/6032193/uploads/IRCYQZ1F4EUM/image.pnghttps://us.v-cdn.net/6032193/uploads/2D5APKV1ZH3B/image.png/forum/discussion/24731/what-is-the-reason-for-error-atomization-model-not-valid-for-the-given-conditions

Double posting is not appreciated.

[RajasekarK123]

Sir I am using 2D axisymmetric n

[RajasekarK123]

/forum/discussion/24731/what-is-the-reason-for-error-atomization-model-not-valid-for-the-given-conditionsDouble posting is not appreciated./forum/discussion/comment/107677#Comment_107677

Actually i did not included any extra details here so i posted again, it wont continue in future. Thanks.n

[Rob]

Thanks. 2d-axi with swirl? n

[RajasekarK123]

I did not try with swirl, i will try it once and update here the result sirn

[RajasekarK123]

I tried with Axisymmetric also, but it leads to the same errorn

[Rob]

What happens if you boost the mass flow as suggests? Please post an image of the geometry, injection point and the injector axis. n

[RajasekarK123]

When i increased my flow rate from 0.97 gps to 1.3 gps i am not getting such error, but in real setup in my laboratory for the given conditions the flow rate is 0.97 gps only, in addition i am not getting my problem converged as shown in the figurennn

[RajasekarK123]

This is geometry and the injection point is at (0.0), geometry measures 450x100 mm in axisyemmetric modeln

[Rob]

Which suggests the atomiser model is designed with certain limits. If you do any nozzle experiments you'll find below a certain flow or pressure instead of a spray you get a dribble of liquid. n

[RajasekarK123]

No sir, i am getting fine atomization with 0.97gps itself. Anyway can you please comment on the convergence of my problem? because after 50000 iterations also its in the particular deviation. shall i consider this as converged.nn

[DrAmine]

Looks fine. What about global mass imbalances and other reports?n

[RajasekarK123]

n

[RajasekarK123]

Residualsnn

[Rob]

How does the flow field look? Remember, we use residuals, mass balance and monitors to judge convergence. Sometimes one or more of the metrics won't converge then we have to use the results to understand why: it's not uncommon for residuals to be as you're seeing because of some transient in the flow field. n

[RajasekarK123]

Temperature fieldn

[Rob]

And how does that compare to what you're expecting? n