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inertial focusing in microfluidic channel

Posted May 11, 2016, 9:34 p.m. EDT Fluid & Heat, Computational Fluid Dynamics (CFD), Microfluidics Version 5.0, Version 5.2a 4 Replies

李 鹏鑫
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Firstly，I want to modeling inertial focusing in straight and curved microfluidic channels（may the channel geometry seems like more complicated ）,just like
cn.comsol.com/story/download/179685/Veryst_Mass_Gen_CN2013.pdf;
here is my model scheme:
1、sovle a CFD probelm(steady) without the particle;
2、calculate the force act on the particle induced by the “stress tensor and pressure ”,just like
www.chem.mtu.edu/~fmorriso/cm310/Comsol/CalculatingFluidForcesonSurfacesinComsol5_2015.pdf
(I know there have “drag force” “lift force”etc.,but I CAN NOT find an explict formula of lift force suited complicated channel)
Lift Force(x)=sphint(r,spf.T_stressx); Lift Force(y)=sphint(r,spf.T_stressy);
The sphint(r, expr) operator computes the surface integral of the expression expr on the surface with radius r around the point in which it is evaluated.;r is the radius of the particle.
3、model particle tracing for fluid flow ,and "Force_x" =lift force(x),"Force_y"=lift force(y)

But the force seems like have influence to the particle, as "the particle inserted at a specific location in the straight channel remian at that location"

So， can anyone give some advises？
4 Replies Last Post May 17, 2016, 5:58 a.m. EDT
李 鹏鑫
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Posted: 9 years ago May 11, 2016, 9:40 p.m. EDT
here is the “force-add” solution；

the particle remain the at the location
here is the “force-add” solution； the particle remain the at the location

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李 鹏鑫
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Posted: 9 years ago May 11, 2016, 10:00 p.m. EDT
I noticed the “equation view> expression”，fpt.Ftx,Fpt.Fty equal to zero;
So I changed the expression “Referring to the other force‘s expression”，
but when start the calculation, there errors happens
I noticed the “equation view> expression”，fpt.Ftx,Fpt.Fty equal to zero; So I changed the expression “Referring to the other force‘s expression”， but when start the calculation, there errors happens
Lee Kyunghun
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Posted: 9 years ago May 13, 2016, 1:30 a.m. EDT
Hi. I am studying about micro fluidics. it's very similar with your interesting things.

When I wanted to simulate about inertial focusing phenomenon, I faced many problem.

first, how to define a force which is acting on the particle.

and second, obviously, even though there is a specific lift force such as shear gradient force, wall induced force something like that. but Comsol doesn't supply it. Only Drag force is supplied.

So I read a many papers, and I found a equation of lift force, and then I could get a results.

Simply, I got a inertial focusing phenomenon in a circular pipe. The particle is assembled as form of circle in a circular pipe. right?

However I could not get a result in a square pipe.

When I applied same lift force, the particle also is assembled as form of circle in a square pipe.

it is not true.

So actually I quit this phenomenon simulation, if you want to get an another information or discuss with me about inertial focusing. let's reply.

Anyway If you will attach your file (Comsol modeling file) on the board, I can easily advice to you.

Thanks for our knowledge.
Hi. I am studying about micro fluidics. it's very similar with your interesting things. When I wanted to simulate about inertial focusing phenomenon, I faced many problem. first, how to define a force which is acting on the particle. and second, obviously, even though there is a specific lift force such as shear gradient force, wall induced force something like that. but Comsol doesn't supply it. Only Drag force is supplied. So I read a many papers, and I found a equation of lift force, and then I could get a results. Simply, I got a inertial focusing phenomenon in a circular pipe. The particle is assembled as form of circle in a circular pipe. right? However I could not get a result in a square pipe. When I applied same lift force, the particle also is assembled as form of circle in a square pipe. it is not true. So actually I quit this phenomenon simulation, if you want to get an another information or discuss with me about inertial focusing. let's reply. Anyway If you will attach your file (Comsol modeling file) on the board, I can easily advice to you. Thanks for our knowledge.
Md Usuf
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Posted: 9 years ago May 17, 2016, 5:58 a.m. EDT
Hi,

I tried to add ODE equations for lift force and particle velocity. But unfortunately, i could not able to simulate fully, because of lack of RAM and poor meshing with my system. I hope ODE for lift force will help.

lets discuss, email me cmd.yousuf@gmail.com

Hi, I tried to add ODE equations for lift force and particle velocity. But unfortunately, i could not able to simulate fully, because of lack of RAM and poor meshing with my system. I hope ODE for lift force will help. lets discuss, email me cmd.yousuf@gmail.com

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