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laser simulation by icoReactingMultiphaseInterFoam |
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#1 |
New Member
Join Date: Dec 2020
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Hi, everyone.
I conducted simulation of laser irradiation with the icoReactingMultiphaseInterFoam solver, however the calculation result is unnatural. If you don't mind, could you give me some advice...? The metal plate with a thickness of 1mm is sandwiched between air (Fig.1), and a Gaussian-type laser (spot diameter: 0.1mm, laser power: 1000W) was irradiated from above for a long time (Fig.2). The thermal conductivity of metal should be higher than that of air, but the temperature distribution shows that air is hotter and the metal temperature remains much lower than the melting temperature (Fig.3). Also, when extracting the temperature of the metal, both the upper and the lower part of the metal are hot (Fig.4). I think the laser energy is absorbed from the electrons on the top of the metal and warms up... I imagined the calculation result that the metal reaches the melting point from the top and melts like a bell, but the result is completely different from that. Is it necessary that the air is treated as an adiabatic gas? And the laser power is quite small? If you have experience with laser irradiation, could you please tell me the correct setting of radiationProperties and treament of air? I'd like to attach my case file, I would appreciate your advice. |
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#2 |
Member
Teresa
Join Date: Nov 2015
Location: germany
Posts: 63
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Hi Amada,
I am working with icoReactingMultiphaseInterFoam as well. Sadly I missed your post. In your radiationProperties file I see that you have specified only one absorptivity, emissivity and E, therefore air and metal react the same way towards your laser. You may want to use something like this (numbers are from my case): Code:
localDensityAbsorptionEmissionCoeffs { alphaNames (alpha.air alpha.melt alpha.metal); aCoeff (0 1e3 1e8); eCoeff (0 0.35 0.35); ECoeff (0 0 0); } Code:
absorptivity absorptivity [0 -1 0 0 0 0 0] 0.1; emissivity emissivity [0 -1 0 0 0 0 0] 1.0; E E [1 -1 -3 0 0 0 0] 0; I haven't checked the whole case, since you probably solved the problem by now anyway. Greetings, Teresa |
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#3 | |
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Harris Daniel S
Join Date: Oct 2017
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Quote:
Hello Teresa, What absorptionEmissionModel did you use to specify the absorptivity, emissivity coefficients individually for the phases? Is constantAbsorptionEmission model good enough? Regards, Harris |
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#4 | |
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Harris Daniel S
Join Date: Oct 2017
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Quote:
Hey Guys! If you want to declare absorptivity, emissivity for individual phases like Teresa did, you'll have to use "localDensityAbsorptionEmission" as your absorptionEmissionModel. Thanks. |
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#5 | |
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Bill
Join Date: Jun 2019
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Quote:
Did you find that 0.35 emissivity coefficients affect your results? Specifically, if you use 0 for the emissivity coefficients, do you get a difference outcome (e.g. T values)? For my simulation, I did not see a difference which is confusing. |
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#6 | |
Member
Teresa
Join Date: Nov 2015
Location: germany
Posts: 63
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Quote:
I wasn't able to simulate different emissivity coefficients yet, or thought it wasn't a priority as long as I have big issues that are probably not from eCoeff. Do you simulate powder or other structures that could could affect each other through emissivity? If you have 0 values for the gas above your solid or liquid and not much structure emissivity can't do much. aCoeff however gave me a lot of headaches. Right now I fight with condensation, as i can't find a kineticgasevaporation model for it, and my vapour behaves strange when kept "hanging". Greetings, Teresa |
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#7 | |
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Sumant
Join Date: Nov 2021
Posts: 13
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Hello Dear Friends,
I am trying "Laser Simulation" by using "icoReactingMultiphaseInterFoam" solver and Laser DTRM radiation model. But I am facing an error, I am unable to recognize the error. So if anyone knows about this error please let me know. I am attaching my code file in Zip format for the reference. Error Quote:
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#8 |
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Join Date: Oct 2017
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Your setFieldsDict is incorrect:
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#9 | |
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Sumant
Join Date: Nov 2021
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Quote:
I modified this but this time also I am facing the same error and also I did modification in the 'decomposeParDict' file but nothing happened. Please suggest me again. |
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#10 | ||||
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Sumant
Join Date: Nov 2021
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Hello Everyone,
I have some doubts regarding units, 1) What is the unit of "molWeight" (in thermophysicalProperties file), g/mol, or kg/mol ? Quote:
And during simulation, I am facing an error (code related to 'rediationProperties' ) Error Quote:
Quote:
Quote:
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#11 | ||
Senior Member
Join Date: Oct 2017
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Quote:
Quote:
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#12 | ||||
New Member
Sumant
Join Date: Nov 2021
Posts: 13
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Dear Krapf,
Quote:
But, I am facing issues in 'absorptionEmissionModel'. Here I am attaching my radiation code file for reference. Quote:
When I am executing this code, it is showing, Quote:
Quote:
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#13 |
Senior Member
Join Date: Oct 2017
Posts: 124
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Not sure if this will solve the problem but try deleting "absorptionEmissionModel constantAbsorptionEmission;". You set absorptionEmissionModel twice.
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#14 | ||
New Member
Sumant
Join Date: Nov 2021
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Hello Krapf,
Quote:
Radiation Properties file... Quote:
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#15 |
Senior Member
Join Date: Oct 2017
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You use alpha.air, alpha.melt and alpha.metal in localDensityAbsorptionEmissionCoeffs.alphaNames. Are this the same names which you have defined in constant/phaseProperties?
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#16 | |
New Member
Sumant
Join Date: Nov 2021
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Hello Krapf,
Quote:
I sincerely thank you for your help. I will definitely let you know when I get any other problems during my simulation. |
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#17 |
New Member
Sumant
Join Date: Nov 2021
Posts: 13
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Hello Friends,
As my simulation is running and I got some results but it is clearly visible some things wrong in my result: Fig-1 and Fig-2. Fig-1 shows the solid and air zone of my geometry, but there is a semi-solid zone at the interface of both, means that the zone separates our solid and air parts. Fig-2 represents the temperature profile and laser position. that white spot represents the laser position (always it is like that only, on a solid surface also), I don't know it is right or wrong. And big confusion related to laser power. When I am using laser power as 1000 to 1e6 then the maximum temperature goes up to 300.5 K to 450 K only, and at 1e7 maximum temperature goes up to 2000 K. So, please give some suggestions on my queries. |
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#18 |
Senior Member
Join Date: Oct 2017
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Regarding Fig 1: You see this "semi-solid zone" because your are displaying point values. ParaView interpolates between solid and air. If you switch to cell values you will see sharp interfaces.
Regarding Fig 2: If you zoom in you will see that the white spot consists of many small dots. This are the starting points of the laser rays which you defined in radiationPropterties. |
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#19 |
New Member
Sumant
Join Date: Nov 2021
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Hello,
1) The simulation result I want is not coming means fig-1 shows my expected result, and fig-2 is showing my real simulation result, which means I am not getting a melt pool like this. So please let me know where I am doing mistakes, and also please let me know which terms I am missing that I should add in my coding. 2) I am still confused related to the laser power value (unit) because at laser power 1000 to 1e6 the maximum temperature goes up to 300.5 K to 700 K only, so I am using 2e6 laser power for getting temperature range 2800-3000 K. So please let me know where I am doing mistakes. I have attached the code file for reference. |
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#20 |
Member
Teresa
Join Date: Nov 2015
Location: germany
Posts: 63
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Hey Yasum,
to me the picture looks like your laser is absorbed not over a small absorption length but over the whole range. You might want to look at this. The absorption coefficient in localdensityAbsorptionEmissonCoeffs is in the unit 1/meter. Try out high values like 1e4 to 1e6 and see if this changes something. Greetings, Teresa |
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