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-   -   help for ANSYS Fluent : cylindrical flow (http://www.cfd-online.com/Forums/fluent/99933-help-ansys-fluent-cylindrical-flow.html)

 slimmsk April 16, 2012 10:24

help for ANSYS Fluent : cylindrical flow

Hello everyone,

I start a project to study digital and it's been 4 months since I started with ANSYS13 FLUENT.

I start by simulating the flow of blood through a vein with the presence of a probe (blood flow between two parallel cylinders) to validate my model.
I can not find the correct profile (I found an acceleration along the cylinder) figure (A), the rate does not stabilize. The flow is along the Z axis

Normally I have to find a profile such that the figure (B)

The conditions I have are:
The vein is modeled by a straight cylinder of diameter D = 25.8mm and length L = 300mm. The probe is modeled by a right cylinder of diameter d = 3.1mm and the same length.
The flow area is S = pi (D ²-d ²) / 4 = 515.245mm ²

The flow is assumed laminar
The walls are assumed fixed and rigid over time.
The blood is assumed Newtonian studied with a density and viscosity 1050Kg/m3 0.0045Kg / (ms)
The temperature is set at 310 ° K (body temperature 37 ° C)
The boundary conditions are imposed
o Input: Q = 3600ml/min therefore a mass flow of 0.0633Kg / s
o Output: P = 399.96 Pa

I use the following configurations on fluent

Model: viscous laminar
Material: Fluid: Blood
Boundary condition: Massflowin =0.0633Kg/s

Pout =399.96Pa

 villager April 16, 2012 16:12

Quote:
 Originally Posted by slimmsk (Post 354902) [LEFT][LEFT] [LEFT][LEFT] Pout =399.96Pa
oK, you set pressure outlet B.C, didn't you?

In case of constant density try to use velocity inlet instead mass flow inlet, as recommended 7.2.1 Using Flow Boundary Conditions

Since blood is Non-Newtonian liquid, you can use Herschel-Buckley, or Cross model for viscosity in Materials dialog.

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