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flow simulation left heart chamber

Posted 19 avr. 2010, 04:06 UTC−4 Bioengineering 5 Replies

Alexandra Heidsieck
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Dear Experts!

I am trying to make a rough model of the blood flow in the left heart chamber.
Therefore, i have a 3-d model of an expanded left ventricle, that i import in Comsol. There i scale it to the approximately right size (100ml) and add the physics (subdomain settings: rho=1000 kg/m3, eta=0.004 Pa s; boundary: 5,7,8 -> outlet, pressure, no viscous stress, p=10 kPa,, 36, 37: inlet, pressure, p=15 kPa,, residue, wall, no slip).
I guess, this is thereabout like in real heart, but Comsol does not find a solution for this problem!
I dont know, why Comsol has so big problems. The inlet and outlet are almost the same size. I can play with pressure, but i does not find a possible solution.

I know, that there a big problems in this model, there is no pumping cycle and the walls are stiff. Unfortunately, i dont know how to implement this...

Does anybody know how to start and stop the blood flow? So that at one time, i have a filling of the heart and after this, the heart will be emptied? Maybe, this would help...

Or it would be a approach to get this static model run with understandable boundary settings...

I attached the model.
I am pleased to answer any question!
And I hope, that anybody can help!

Thanks a lot!

Attachments:

5 Replies Last Post 26 avr. 2010, 08:48 UTC−4
Danial Tz
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Posted: 1 decade ago 19 avr. 2010, 04:20 UTC−4
Isn't that the flow inside the heart is turbulent? Your model is using a laminar flow model. In that case, you should take care of turbulence.
Isn't that the flow inside the heart is turbulent? Your model is using a laminar flow model. In that case, you should take care of turbulence.
Alexandra Heidsieck
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Posted: 1 decade ago 19 avr. 2010, 05:12 UTC−4
Thanks for your answer!
How can i take care of turbulent flow or how can i consider this in the simulation?
Thanks for your answer! How can i take care of turbulent flow or how can i consider this in the simulation?
Danial Tz
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Posted: 1 decade ago 19 avr. 2010, 06:06 UTC−4
AFAIK, there at least two methods implemented in Comsol, and they are explained in detail in the manual. Also, there are several models already available in comsol for you to check them.

i.e. www.comsol.com/showroom/gallery/498/
AFAIK, there at least two methods implemented in Comsol, and they are explained in detail in the manual. Also, there are several models already available in comsol for you to check them. i.e. http://www.comsol.com/showroom/gallery/498/
Alexandra Heidsieck
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Posted: 1 decade ago 19 avr. 2010, 09:23 UTC−4
again, thanks for your answer!
i tried to make the simulation in the k-e-Turbulence-Model, but i dont get it working.
There are always some errors.
I cant imagine, where the problem is. I just have a body, with two holes in it. One for inlet and one for outlet. That cant be such a problem.
I would be glad, if i could get the simulation working with any boundary settings, but i dont know which i should use...

you find attached a model, which is smaller than the correct one. with settings like:
pressure outlet: 150 Pa and velocity inlet: 0.6 m/s.
this one does come to an end, but when i scale the geometry to real size, it wont...

i ll try to get this small one running in the turbulence model. maybe there i ll see what is wrong.
again, thanks for your answer! i tried to make the simulation in the k-e-Turbulence-Model, but i dont get it working. There are always some errors. I cant imagine, where the problem is. I just have a body, with two holes in it. One for inlet and one for outlet. That cant be such a problem. I would be glad, if i could get the simulation working with any boundary settings, but i dont know which i should use... you find attached a model, which is smaller than the correct one. with settings like: pressure outlet: 150 Pa and velocity inlet: 0.6 m/s. this one does come to an end, but when i scale the geometry to real size, it wont... i ll try to get this small one running in the turbulence model. maybe there i ll see what is wrong.

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Alexandra Heidsieck
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Posted: 1 decade ago 26 avr. 2010, 08:48 UTC−4
i dont get it working.

is there a way to simulate the inflow into an empty volume and after this, simulate the outflow of the liquid?

maybe with this, the physics would be represented better...
i dont get it working. is there a way to simulate the inflow into an empty volume and after this, simulate the outflow of the liquid? maybe with this, the physics would be represented better...

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