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Dean Flow Modelling in MicroChannels

Posted 24 sept. 2015, 06:15 UTC−4 MEMS & Nanotechnology, MEMS & Piezoelectric Devices, Microfluidics, Structural Mechanics Version 5.0 3 Replies

Utku Sönmez
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Hi,

I'm trying to model Dean Flow in a Spiral Microchannel for further application of Passive Cell Separation.

Since Dean Flow is observed basically on the plane which is perpendicular to the downstream fluid flow, it requires 3D modelling of channel geometry. ( Here there is a schematic explanation: pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/Articleimage/2010/CS/b915999c/b915999c-f17.gif )

I modelled the spiral geometry, defined the material as water, did 'finer' mesh, specified the inlet and outlet, and their corresponding boundary conditions as velocity, where the outlet velocity is half of the inlet velocity since there is one inlet and two outlets with same cros-sectional areas.

I did all of this in Creeping Flow module... Actually this might be problematic since the Reynold's number in the system is 1.27 ( channel cros-section : 130x500 um , and inlet velocity : 7.6 mm/s )


When I tried solve it for Stationary Flow, I couldn't get a convergence after waiting 36 hours ( Here is a screenshoot that i took just befor cancelling the computation : postimg.org/image/48uqj45wn/ )

Are there anyone who have modelled Dean Flow before?

At what point I'm making a wrong thing?

Any advice or suggestion will be appreciated :)

Thanks in advance
3 Replies Last Post 6 oct. 2015, 05:47 UTC−4
Md Usuf
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Posted: 9 years ago 2 oct. 2015, 05:36 UTC−4
Hi Utku,

I also modelled the similar spiral channel. I selected user defined model and could able to simulate the laminar flow physics and do not get convergence problem, Also I use particle tracing module to see the effect of dean flow on the particle. But unfortunately, I m not able to see the effect. I don t know what had gone wrong with the design. I believe the design is Ok. I m bother that, any equations for dean velocity needs to incorporated somewhere in the initial BC's?
Looking for somebody's help.

Thanks

Yousuf
Hi Utku, I also modelled the similar spiral channel. I selected user defined model and could able to simulate the laminar flow physics and do not get convergence problem, Also I use particle tracing module to see the effect of dean flow on the particle. But unfortunately, I m not able to see the effect. I don t know what had gone wrong with the design. I believe the design is Ok. I m bother that, any equations for dean velocity needs to incorporated somewhere in the initial BC's? Looking for somebody's help. Thanks Yousuf
Utku Sönmez
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Posted: 9 years ago 2 oct. 2015, 10:48 UTC−4
Hi Yousuf, I think I found the point at which I made mistake. As you told, the problem was about the boundary conditions. I had given a outlet velocity boundary condition together with the inlet velocity boundary condition. When I change the velocity boundary condition to 'zero pressure' boundary condition, the solution converged.

Now I'm dealing with the particle traction module :)

Utku.
Hi Yousuf, I think I found the point at which I made mistake. As you told, the problem was about the boundary conditions. I had given a outlet velocity boundary condition together with the inlet velocity boundary condition. When I change the velocity boundary condition to 'zero pressure' boundary condition, the solution converged. Now I'm dealing with the particle traction module :) Utku.
Md Usuf
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Posted: 9 years ago 6 oct. 2015, 05:47 UTC−4
Have you got an idea where to incorporate inertial force and dean force equations in particle tracing module, so that, drag force along with this two forces results in particle separation.

Thanks
Yousuf
Have you got an idea where to incorporate inertial force and dean force equations in particle tracing module, so that, drag force along with this two forces results in particle separation. Thanks Yousuf

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