[Jikst]

First off I am new to cfd and therefore openfoam. I would like to simulate the flow of water through this spray nozzle. I have 3 different attachable nozzle patterns so will need to simulate 3 times. Water will come from the bottom horizontal hole (1/4") 60psi and exit through the vertical nozzle spray pattern. I am interested in how the flow will behave outside of the nozzle(spray pattern, spread, reach of flow, etc.)

Is there a case available in tutorials or elsewhere that can help me with this.

[gkarlsen]

Advanced topic, so maybe not the best place to get started....

Typically spray simulations make use of a Eulerian-Lagrangian approach. In openFoam you can take a look at "sprayFoam" and the tutorial "aachenBomb". This solver will provide you with the data regarding pattern, penetration, breakup etc. However, in sprayFoam you predefine the spray cloud. The cloud properties are obviously not known for your custom nozzle designs. Therefore I guess you would have to first determine the cloud characteristics by use of a multiphase VOF approach. This is going to be computationally expensive as you need a highly refined mesh to capture small droplets combined with high velocities (which translates to small time steps). Something along these lines I guess:

https://www.researchgate.net/publica...USING_OPENFOAM

Edit: Also the interFoam tutorial "nozzleFlow2D" might be worth studying

Good luck

[Jikst]

Thank you gkarlsen!

Have been using OF for a couple months now but still relatively new. Good to know I was on the right track. I actually read that article, did not know I would need to know spray cloud to use sprayFoam. I have actually been modifying a laminar VOF case for this problem (I see LES would be more appropriate).

But my first set of difficulties I came across was meshing problems. Trying to mesh both internal flow and external. ideasUnvToFoam did not want to work for nozzle, and now SHM is giving me problems as well (face pyramid vol).

Will keep trying even though its too advanced for me, simply because I'm interested/curious now about this problem. Thank you for the reply your help is much appreciated.

[Adriagc2]

Originally Posted by Jikst

First off I am new to cfd and therefore openfoam. I would like to simulate the flow of water through this spray nozzle. I have 3 different attachable nozzle patterns so will need to simulate 3 times. Water will come from the bottom horizontal hole (1/4") 60psi and exit through the vertical nozzle spray pattern. I am interested in how the flow will behave outside of the nozzle(spray pattern, spread, reach of flow, etc.)

Is there a case available in tutorials or elsewhere that can help me with this.

Hello Jikst,

I'm currently working on a similar problem. I would like to study the spray and atomization of two water impinging jets. I have tried to use multiple Lagrangian solvers and the MPPICFoam tutorial - injectionChannel is the closest I am currently to simulate the case. However, it is far from good and I know sprayFoam is the best solver to make this kind of simulations but I don't know how to modify the only public case I have found, the aachenBomb, in order to get rid of all the chemkin and combustion stuff and just see a nice spray coming out of the injector. Could you help me?

Kind regards,
Adrià

[moss-openfoam]

Originally Posted by Adriagc2

Hello Jikst,

I'm currently working on a similar problem. I would like to study the spray and atomization of two water impinging jets. I have tried to use multiple Lagrangian solvers and the MPPICFoam tutorial - injectionChannel is the closest I am currently to simulate the case. However, it is far from good and I know sprayFoam is the best solver to make this kind of simulations but I don't know how to modify the only public case I have found, the aachenBomb, in order to get rid of all the chemkin and combustion stuff and just see a nice spray coming out of the injector. Could you help me?

Kind regards,
Adrià

Dear Adriagc2,Please do you now have a proper solution to this problem? I'm having the same problem as you were, and would be very grateful if you could provide me with some useful information.

[Adriagc2]

Originally Posted by moss-openfoam

Dear Adriagc2,Please do you now have a proper solution to this problem? I'm having the same problem as you were, and would be very grateful if you could provide me with some useful information.

Hi Tomas! I did a lot of research on the subject and you can find my final results in the following link. Hope you find it helpful.
https://github.com/adriaGonzalezCano...Adria-Gonzalez

[moss-openfoam]

Originally Posted by Adriagc2

Hi Tomas! I did a lot of research on the subject and you can find my final results in the following link. Hope you find it helpful.
https://github.com/adriaGonzalezCano...Adria-Gonzalez

First of all thank you for replying me in such a timely manner. I have some doubts about your work. Why did you end up using the MPPICFoam solver instead of the SprayFoam solver. If my goal is to simulate the spray of a centrifugal nozzle with water as the medium, and finally obtain the spray characteristics of the nozzle, how should I modify your calculation example? Thanks!

[Adriagc2]

Originally Posted by moss-openfoam

First of all thank you for replying me in such a timely manner. I have some doubts about your work. Why did you end up using the MPPICFoam solver instead of the SprayFoam solver. If my goal is to simulate the spray of a centrifugal nozzle with water as the medium, and finally obtain the spray characteristics of the nozzle, how should I modify your calculation example? Thanks!

Hello, no problem in answering your questions. I also struggled a lot with this particular problem a while ago. To answer your question I recommend you this paper (https://ep.liu.se/ecp/142/099/ecp17142099.pdf) which gives a general overview of some of the available gas-solids (Eulerian-Eulerian and EulerianLagrangian). In my case I chose the MP-PIC solver as I was trying to simulate a very dense cloud of particles but you may want to check the other solvers available that may offer different advantages (page 2). Also, if you want the full version of my work on the subject, you can check it on the following link:
https://upcommons.upc.edu/handle/2117/374242

I am not an expert on the field and I don't have a precise answer for your particular problem, however if you have more doubts don't hesitate to ask

[moss-openfoam]

Originally Posted by Adriagc2

Hello, no problem in answering your questions. I also struggled a lot with this particular problem a while ago. To answer your question I recommend you this paper (https://ep.liu.se/ecp/142/099/ecp17142099.pdf) which gives a general overview of some of the available gas-solids (Eulerian-Eulerian and EulerianLagrangian). In my case I chose the MP-PIC solver as I was trying to simulate a very dense cloud of particles but you may want to check the other solvers available that may offer different advantages (page 2). Also, if you want the full version of my work on the subject, you can check it on the following link:
https://upcommons.upc.edu/handle/2117/374242

I am not an expert on the field and I don't have a precise answer for your particular problem, however if you have more doubts don't hesitate to ask

Thank you very much for your suggestions, I will study and read these materials carefully. May I ask you one more question? I also studied many calculation examples, but I found that the names and contents of the dictionary files corresponding to different calculation examples 0 and constant folders are not the same, so where should I learn to call different solvers and write different dictionary files? This is why I want to find a specific calculation case. Thanks!

[Adriagc2]

Originally Posted by moss-openfoam

Thank you very much for your suggestions, I will study and read these materials carefully. May I ask you one more question? I also studied many calculation examples, but I found that the names and contents of the dictionary files corresponding to different calculation examples 0 and constant folders are not the same, so where should I learn to call different solvers and write different dictionary files? This is why I want to find a specific calculation case. Thanks!

If I understand correctly, you are new in the field of OpenFOAM and you are trying to figure out how to solve your case, which looks pretty complicated before having learnt the basics of this software.

First of all, even if it is a free-to-use software, it is hard to learn and all the tutorials may not be intuitive to understand as every solver may have its own formulation. In the last document I sent you, you will find an introduction to this software (page 41), which I really recommend you reading as it has all the knowledge and information I had to investigate in order to know how to use it.

To answer your question, you may notice that, even if the tutorials are well-known for the community for being basic examples of use of every solver, they have been done by different users, which is why you may see different names and contents in the different 0 and constant folders. This tutorials allow people with little experience with the solver to be able to modify the example case with their own parameters and geometry, which is what I did. I modified the doublet Injector Channel case from the MPPIC Foam TUTORIALS subfolder. (see: https://www.youtube.com/watch?v=wslQ...annel=WenwuShi). I'm sure this example case can also be useful for solving your problem.

Hope I answered your question,

Kind regards.

[moss-openfoam]

Originally Posted by Adriagc2

If I understand correctly, you are new in the field of OpenFOAM and you are trying to figure out how to solve your case, which looks pretty complicated before having learnt the basics of this software.

First of all, even if it is a free-to-use software, it is hard to learn and all the tutorials may not be intuitive to understand as every solver may have its own formulation. In the last document I sent you, you will find an introduction to this software (page 41), which I really recommend you reading as it has all the knowledge and information I had to investigate in order to know how to use it.

To answer your question, you may notice that, even if the tutorials are well-known for the community for being basic examples of use of every solver, they have been done by different users, which is why you may see different names and contents in the different 0 and constant folders. This tutorials allow people with little experience with the solver to be able to modify the example case with their own parameters and geometry, which is what I did. I modified the doublet Injector Channel case from the MPPIC Foam TUTORIALS subfolder. (see: https://www.youtube.com/watch?v=wslQ...annel=WenwuShi). I'm sure this example case can also be useful for solving your problem.

Hope I answered your question,

Kind regards.

Thank you very much for your paper. After studying for the past few days, I found that your paper is very similar to the research method I designed before, and I have reproduced the results in your paper. But there is one thing I don't quite understand how you get the water spray velocity in post-processing (with your Python code). Looking forward to your answer, thank you very much!

[moss-openfoam]

Originally Posted by Adriagc2

If I understand correctly, you are new in the field of OpenFOAM and you are trying to figure out how to solve your case, which looks pretty complicated before having learnt the basics of this software.

First of all, even if it is a free-to-use software, it is hard to learn and all the tutorials may not be intuitive to understand as every solver may have its own formulation. In the last document I sent you, you will find an introduction to this software (page 41), which I really recommend you reading as it has all the knowledge and information I had to investigate in order to know how to use it.

To answer your question, you may notice that, even if the tutorials are well-known for the community for being basic examples of use of every solver, they have been done by different users, which is why you may see different names and contents in the different 0 and constant folders. This tutorials allow people with little experience with the solver to be able to modify the example case with their own parameters and geometry, which is what I did. I modified the doublet Injector Channel case from the MPPIC Foam TUTORIALS subfolder. (see: https://www.youtube.com/watch?v=wslQ...annel=WenwuShi). I'm sure this example case can also be useful for solving your problem.

Hope I answered your question,

Kind regards.

Dear Adriagc2，Please forgive me for having so many questions as a newbie. I researched your openfoam code, but found that you don't use models (like KHRT and TAB) for the primary and secondary breakage of the atomized liquid. If I want to add these models, I must know the writing format of the .properties file. How can I learn the writing format of the specific dictionary file? (I have read all the information you provided, and I can understand the idea, but I cannot get the specific writing method). By the way, your paper is well written and helped me a lot.

[Adriagc2]

Originally Posted by moss-openfoam

Dear Adriagc2，Please forgive me for having so many questions as a newbie. I researched your openfoam code, but found that you don't use models (like KHRT and TAB) for the primary and secondary breakage of the atomized liquid. If I want to add these models, I must know the writing format of the .properties file. How can I learn the writing format of the specific dictionary file? (I have read all the information you provided, and I can understand the idea, but I cannot get the specific writing method). By the way, your paper is well written and helped me a lot.

Dear Tomas,

I am glad I could help you with my work, that means a lot for me. The postprocessing tools I used can be found in the Software ParaView which can be accessed by simply typing $paraFoam in the terminal of any simulation you have run (you must have the time folders). In this software you will be able to find all the graphics you are looking for and for more complex things I suggest you to look for more documentation online.

As for the particle breakage of the liquid, I did not much investigate about it. From what I remember, the solver I was using used an approach which didn't solve particle to particle interaction (contrary to DPMFoam), i.e. MPPIC uses some model for the particle collision rather than calculating them directly. In addition, my simulation assumed that the fluid was already atomized from the beginning, thus, it didn't require any type of model for particle breakage, but only for particle cloud properties as you can check in the cloud properties dictionary. Nontheless, I am sure there is still a lot of room for improvement but I am affraid I didn't research a lot on that specific question.

Best regards.

[moss-openfoam]

Originally Posted by Adriagc2

Dear Tomas,

I am glad I could help you with my work, that means a lot for me. The postprocessing tools I used can be found in the Software ParaView which can be accessed by simply typing $paraFoam in the terminal of any simulation you have run (you must have the time folders). In this software you will be able to find all the graphics you are looking for and for more complex things I suggest you to look for more documentation online.

As for the particle breakage of the liquid, I did not much investigate about it. From what I remember, the solver I was using used an approach which didn't solve particle to particle interaction (contrary to DPMFoam), i.e. MPPIC uses some model for the particle collision rather than calculating them directly. In addition, my simulation assumed that the fluid was already atomized from the beginning, thus, it didn't require any type of model for particle breakage, but only for particle cloud properties as you can check in the cloud properties dictionary. Nontheless, I am sure there is still a lot of room for improvement but I am affraid I didn't research a lot on that specific question.

Best regards.

Dear Adriagc，recently, I continued to study your thesis, and I found that your 42nd reference was written by a student of my supervisor, which is also a wonderful fate. The problem is this, I found that your calculation example has an omega dictionary file in the 0 folder, but you did not mention it in the article, and the k-eplison model is also used, which makes me puzzled. Hope to get your answer, I wish you a happy life!

[Adriagc2]

Originally Posted by moss-openfoam

Dear Adriagc，recently, I continued to study your thesis, and I found that your 42nd reference was written by a student of my supervisor, which is also a wonderful fate. The problem is this, I found that your calculation example has an omega dictionary file in the 0 folder, but you did not mention it in the article, and the k-eplison model is also used, which makes me puzzled. Hope to get your answer, I wish you a happy life!

Hello Tomas,

I'm glad to hear that, these little coincidences make me think how close the scientific community is. Sorry for the late reply, however I think I'm not capable of answering your question at 100%. If I remember correctly, I described two turbulence models in my model in order to run both of them, but at some point I decided one of the two was better for my specific case. I'm glad you have found useful all my documentation and if you have more doubts do not hesitate to contact me via email (adriagc100@gmail.com).

I'm really greatful that my work has had a purpose, kind regards.

[Adriagc2]

Originally Posted by moss-openfoam

Dear Adriagc，recently, I continued to study your thesis, and I found that your 42nd reference was written by a student of my supervisor, which is also a wonderful fate. The problem is this, I found that your calculation example has an omega dictionary file in the 0 folder, but you did not mention it in the article, and the k-eplison model is also used, which makes me puzzled. Hope to get your answer, I wish you a happy life!

Dear Tomas,

I trust this message finds you well. I am writing you to learn about the progress of your recent work. If it is not too much trouble, could you send me the outcomes achieved? I am keen to explore the results.

Thank you for your attention to this matter.

Best regards,

Adrià