Learning Forum

[soto6942]

Greetings to all.

I comment on the following concern and problem that I currently have. I am working with a pipe of length 20 [m] and radius 1 [m], where a Bingham fluid flows, within the parameters I have is that its inlet velocity is 0.1 [m / s], Re = 20, Pressure output 0 [Pa] and its respective rheology of the Bingham fluid. As an additional fact, for each variation of the length meter, the pressure must vary 2 [Pa]. (Important data), that is to say that in this case the inlet pressure should be 40 [Pa]. But at the time of solving it in CFX the inlet pressure is much higher even having it placed in the setup with 40 [Pa]. How can I solve or change the setup to achieve the desired inlet pressure?

 

[soto6942]

UP

[Rob]

If you set the flow rate the solver will calculate the pressure needed to give this amount of flow. If you set the pressure the flow will adjust to that dP.  It's usually better to set a flow rate otherwise convergence can be difficult. 

If the pressure is very different to the experiment, what could be causing this? 

[soto6942]

So it is better to add only one input parameter? In this case the input speed?

 

And I can't understand why the large pressure difference occurs, since the mesh has a good convergence and the fluid develops successfully.