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-   -   Can this simulation be created using CFD? (https://www.cfd-online.com/Forums/main/126526-can-simulation-created-using-cfd.html)

sur4j November 20, 2013 02:29

Can this simulation be created using CFD?
 
I want to create a simulation in which the viscosity of the material varies with time and temperature, by this I mean if you place this material on a plate at constant temperature,over time its viscosity will change. The viscosity of the material will initial decrease and then after time t it will start increasing at an exponential rate.

I would like to simulate this for varying geometries, temperatures and materials. Is this even possible to simulate using CFD or does it require a different simulation type? If possible using CFD could anyone give me any guidance on what I need to understand before attempting something like this?

FMDenaro November 20, 2013 04:36

Quote:

Originally Posted by sur4j (Post 462650)
I want to create a simulation in which the viscosity of the material varies with time and temperature, by this I mean if you place this material on a plate at constant temperature,over time its viscosity will change. The viscosity of the material will initial decrease and then after time t it will start increasing at an exponential rate.

I would like to simulate this for varying geometries, temperatures and materials. Is this even possible to simulate using CFD or does it require a different simulation type? If possible using CFD could anyone give me any guidance on what I need to understand before attempting something like this?

do you have a physical model for the viscosity? do you have a mathematical model describing the law of variation mu=mu(Theta, t) ?

sur4j November 20, 2013 08:05

I can obtain rehometer readings which generate a graph which shows the torque versus time readings for a set temperature, is this what would be required? If not I can obtain further information.

FMDenaro November 20, 2013 08:39

Quote:

Originally Posted by sur4j (Post 462712)
I can obtain rehometer readings which generate a graph which shows the torque versus time readings for a set temperature, is this what would be required? If not I can obtain further information.


are you able to create a database and use continuous values by interpolation of discrete datas? If so, you can do CFD simulation using an access to such datas to compute viscosity as function of time and temperature

sur4j November 20, 2013 15:40

I can obtain the values to create this database however, what would I use to create this, would it be something that is created within the CFD software used or an external software package?

Is this considered a non-isothermal flow simulation?

Could this be simulated using some sort of standard solidification model?

The viscosity variations occur because of a reaction within the material, therefore would this require some form of a reaction solver or should the database values cover this?

FMDenaro November 20, 2013 17:00

Quote:

Originally Posted by sur4j (Post 462781)
I can obtain the values to create this database however, what would I use to create this, would it be something that is created within the CFD software used or an external software package?

Is this considered a non-isothermal flow simulation?

Could this be simulated using some sort of standard solidification model?

The viscosity variations occur because of a reaction within the material, therefore would this require some form of a reaction solver or should the database values cover this?


Consider that mu=mu(Theta,t) is required in the momentum and energy equation; if you can prescribe it by some mathematical law or experimental datas, you can set as boundary condition. Otherwise, you should solve time-by-time the reaction equation that governs its evolution, coupling that to the flow equations.

sur4j November 20, 2013 17:23

The material I am working with is rubber and the process is known as curing, the test results obtained which the mathematical model will be generated from apply to a simple block geometry of a small volume. For larger geometries the time required for this solidification (curing of rubber) is much longer, will using mu=mu(Theta,t) take this into account or will I have to use the time-by-time reaction equation?


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