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Defining a polynomial viscosity depending on temperature |
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September 28, 2020, 04:28 |
Defining a polynomial viscosity depending on temperature
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#1 |
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Muhammed Emin POLAT
Join Date: Sep 2020
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Hello all,
I'm currently trying to run an analysis using temperature integrated simpleFoam. As of my observations, temperature range for the fluid is between 20-50 C and due to this large range, viscosity changes in a wide range which leads my computation into a big error, at about 50%. So here is my question. I would like to apply a curve-fitting to viscosity of my fluid flowing through and integrate it in the OpenFOAM by NOT using a non-Newtonian approach. Because fluid is definetely Newtonian. How can I achieve it? |
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September 29, 2020, 05:30 |
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#2 |
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Tobias Holzmann
Join Date: Oct 2010
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There are more options. Either you switch to, e.g., rhoSimpleFoam and use a polynomial approach or you derive your current solver (simpleFoam) and implement new volScalarFieldīs which relates to temperature and viscosity. Then you have to solve an appropriate temperature/energy equation and calculate the viscosity based on your temperature field.
Probably, the rhoSimpleFoam solver fits better as you donīt have to program anything yourself. An example: Code:
thermoType { type heRhoThermo; mixture pureMixture; transport polynomial; thermo hPolynomialt; equationOfState polynomial; specie specie; energy sensibleEnthalpy; }
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Keep foaming, Tobias Holzmann |
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September 30, 2020, 02:30 |
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#3 | |
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Muhammed Emin POLAT
Join Date: Sep 2020
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Thank you for your reply Tobi,
The thing is I would like to compute the viscosity for each cell using its temperature and have this value used in governing equations. I don't want any contour for viscosity, to say. Do you have any recommendation for this goal? Quote:
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September 30, 2020, 02:36 |
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#4 |
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Tobias Holzmann
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Well, I am not sure if you read my reply or not because I wrote the stuff you need. Hence, I don't get your statement.
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Keep foaming, Tobias Holzmann |
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September 30, 2020, 04:06 |
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#5 |
New Member
Muhammed Emin POLAT
Join Date: Sep 2020
Posts: 7
Rep Power: 5 |
Thank you for your help and kindness.
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September 30, 2020, 04:52 |
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#6 |
Super Moderator
Tobias Holzmann
Join Date: Oct 2010
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Just a quick question. Is it clear to you now or not? I don't have the feeling that my statement is sufficient for you or maybe I misunderstood your inquiry!?
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Keep foaming, Tobias Holzmann |
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