Phase change from powder to liquid and back to solid

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Hi everyone, I am simulating Laser Powder Bed Fusion (LPBF) process and have modelled powder layer as a continuous-scale. I have coupled heat transfer in solid and fluids with laminar flow. I want to know how I can model the phase change for powder as it will first melt to liquid and then will solidify into solid. I want to know how to do this in COMSOL. Using phase change would convert back it to the same material. So, how to make it one way such that it first converts the powder into liquid and later liquid is converted to solid. More information: Properties like density, thermal conductivity and specific heat capacity of powder layer properties is defined as an average of air and solid based on volume fraction.


3 Replies Last Post 21.07.2025, 18:00 MESZ
Edgar J. Kaiser Certified Consultant

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Posted: 1 week ago 11.07.2025, 19:23 MESZ

You might consider to do it in two steps. First melt the powder and use this result as start for the second solidification step.

Cheers Edgar

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Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
You might consider to do it in two steps. First melt the powder and use this result as start for the second solidification step. Cheers Edgar

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Posted: 12 hours ago 21.07.2025, 14:49 MESZ

Dear Edgar,

Thanks for the response. Here the simulation is in transient domain. While the laser is moving and melting the powder (continuum scale model - mixture of air and solid), solidification is also taking place at the location where the powder was melted earlier. If I model first just transition from powder to liquid, it will take back powder properties only. Kindly let me know how to go ahead with this.

Regards Love Kush Tak

Dear Edgar, Thanks for the response. Here the simulation is in transient domain. While the laser is moving and melting the powder (continuum scale model - mixture of air and solid), solidification is also taking place at the location where the powder was melted earlier. If I model first just transition from powder to liquid, it will take back powder properties only. Kindly let me know how to go ahead with this. Regards Love Kush Tak

Edgar J. Kaiser Certified Consultant

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Posted: 8 hours ago 21.07.2025, 18:00 MESZ

I see. This means you will need to implement some kind of hysteresis approach. COMSOL has hysteresis implemented into structural and magnetic physics but not in thermal physics as far as I am aware of. Hysteresis can still be implemented by extra equations and the previous solution options. I recommend to do a search in the application library/gallery and in the blog to get some ideas.

Good luck, Edgar

-------------------
Edgar J. Kaiser
emPhys Physical Technology
www.emphys.com
I see. This means you will need to implement some kind of hysteresis approach. COMSOL has hysteresis implemented into structural and magnetic physics but not in thermal physics as far as I am aware of. Hysteresis can still be implemented by extra equations and the previous solution options. I recommend to do a search in the application library/gallery and in the blog to get some ideas. Good luck, Edgar

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