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Unusual condition between two fluids

Guilherme Rosati Mecelis

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Hello, i`m new here, then sorry if this is a silly question...

I need to set the follow condition in the interface between two fluids:

ro_v*u_v*hfg = ro_l*u_l*hfg = lambda_v*(dTv/dx) - lambda_eff*(dTl/dx)

Where:
ro = density
u = velocity
lambda = condutivity
hfg = latent heat

That is a balance of heat flux.
I must find an boundary condition that lets me set the velocities in the interface, for the two fluids, following that condition.

Someone have any idea, please??

2 Replies Last Post 11.04.2013, 18:21 GMT-4
Niklas Rom COMSOL Employee

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Posted: 1 decade ago 10.04.2013, 08:47 GMT-4
I wouldn't say that is very unusual. I guess you are doing phase change/melting...
Check this model, it does exactly what you want to do:
www.comsol.com/showroom/gallery/6234/
even if in this case it is melting and involves one solid and one fluid:

Niklas



Hello, i`m new here, then sorry if this is a silly question...

I need to set the follow condition in the interface between two fluids:

ro_v*u_v*hfg = ro_l*u_l*hfg = lambda_v*(dTv/dx) - lambda_eff*(dTl/dx)

Where:
ro = density
u = velocity
lambda = condutivity
hfg = latent heat

That is a balance of heat flux.
I must find an boundary condition that lets me set the velocities in the interface, for the two fluids, following that condition.

Someone have any idea, please??


I wouldn't say that is very unusual. I guess you are doing phase change/melting... Check this model, it does exactly what you want to do: http://www.comsol.com/showroom/gallery/6234/ even if in this case it is melting and involves one solid and one fluid: Niklas [QUOTE] Hello, i`m new here, then sorry if this is a silly question... I need to set the follow condition in the interface between two fluids: ro_v*u_v*hfg = ro_l*u_l*hfg = lambda_v*(dTv/dx) - lambda_eff*(dTl/dx) Where: ro = density u = velocity lambda = condutivity hfg = latent heat That is a balance of heat flux. I must find an boundary condition that lets me set the velocities in the interface, for the two fluids, following that condition. Someone have any idea, please?? [/QUOTE]

Guilherme Rosati Mecelis

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 11.04.2013, 18:21 GMT-4

I wouldn't say that is very unusual. I guess you are doing phase change/melting...
Check this model, it does exactly what you want to do:
www.comsol.com/showroom/gallery/6234/
even if in this case it is melting and involves one solid and one fluid:

Niklas



Thanks Niklas, that helped me a little, but i still have one problem...

My interface condition is between two fuids, then there will need to be a velocity definition in both domains. Its a discontinuity, thats physically not happens, but is a mathematical aproximation to an boiling effect.

I don't know if I'm clear enough, but i'm trying to simulate an boiling effect, but simplified. I'm not using phase change or moving boundaries.

If I could define different velocities for the domains in the different sides of my boundary, my problem would be solved, but i cant find a module that do this... ^^


[QUOTE] I wouldn't say that is very unusual. I guess you are doing phase change/melting... Check this model, it does exactly what you want to do: http://www.comsol.com/showroom/gallery/6234/ even if in this case it is melting and involves one solid and one fluid: Niklas [/QUOTE] Thanks Niklas, that helped me a little, but i still have one problem... My interface condition is between two fuids, then there will need to be a velocity definition in both domains. Its a discontinuity, thats physically not happens, but is a mathematical aproximation to an boiling effect. I don't know if I'm clear enough, but i'm trying to simulate an boiling effect, but simplified. I'm not using phase change or moving boundaries. If I could define different velocities for the domains in the different sides of my boundary, my problem would be solved, but i cant find a module that do this... ^^

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