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-   -   filling cylinder (https://www.cfd-online.com/Forums/fluent/71804-filling-cylinder.html)

f_panahizadeh January 15, 2010 04:55

filling cylinder
 
i'm investigating about CFD simulation of filling a cylinder.
I consider asymmetric, unsteady, compressible, turbulent flow, real gas.
When I consider the pressure inlet boundary condition and applied variation of it by using a UDF the flow after about 10 second diverged. I think it caused by the variation of mass flow inlet so how I can control or specify mass flow inlet when use the pressure inlet boundary condition in Fluent?

herntan January 18, 2010 00:41

use mass flow inlet boundary condition.
Pressure inlet is impossible to control the mass flow. pressure and mass flow is inter-related to each other.

f_panahizadeh January 18, 2010 00:48

Thanks for your answer
please clear how i can define the pressure variation by using the mass boundary condition?
thanks in advance

herntan January 18, 2010 01:31

mass flow rate will automatically create the pressure.
flow always flow from high pressure to low pressure. When u define mass flow rate, the pressure is already there, its impossible to set something which already fixed.

I think u might dealing with something else, please carify ur problem with picture and explain in detail.

f_panahizadeh January 18, 2010 03:52

i should write a UDF for defining mass flow rate varation via time or not?( the pressure of the inlet flow varied from 1bar to 40 bar in 40 seconds and i'm investigating to find temperature field within cylinder via time)


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