[chamounet]

hello,

I'm working on a simulation of a suction turbine to have the output (rpm and moment) due to the action of the suction of the air through the turbine.

my system is like that:

-a velocity input with a negative velocity value ( due to the suction of a vacuum cleaner)
-the turbine which is kind of a radial fan
-the output which is a box with several little holes as a pressure output of 0 Pa (atmospheric value)

I have some trouble simulating the system with the DFBI model and displaying it in a scalar scene

I tried the boat on a wave tutorial for star-CCM+ but don't know if in my case, i need to use the VOF waves or not and how to display the result.

When i run my simulation my mesh disapear gradually with the iteration running.

if someone can help me (or if someone have access to a tutorial for the DFBI module in my case), i will be really gratefull.

Thanks in advance

[ping]

you should be doing this like the fan tutorial and using mrf motion rather than dfbi

and it sounds like you dont need vof either

the only reason to use dfbi is if you want the rotation to be free and do an unsteady run eg to model the start-up of the rotation

[chamounet]

Hello and thanks for the response,

I have just one question: with the mrf motion, it is the fan that put the air in motion not the air pressure that put the fan in rotation? am I right?

and my application will have cycle of 1 minute not more so the start up of the rotation is kind of important

I will try to do the fan simulation. thanks

[ping]

yes with mrf the fan stays stationary but with an applied rpm so you predict flow and pressure but it can be used in transient mode and change the rpm with time

but if you know the flow etc and want to predict fan rpm then it is better to use dfbi

[chamounet]

it's exactly that: i have as an input the air flow condition and want to predict the value of the rotation per muinute of the fan and the moment on the fan axis but i have some trouble simulating it,
the boat on a wave is not the same DFBI model that i want to simulate but can't find one with the same characteristic.

on the boath tutorial, there is only 1 region with the duifferent boundary but in the mrf fan tutorial there is 2, should i have 2 region with interface or only 1?

i simulate with 1 region and the 6DOF body selected for only the fan boundaries but after simulation, it looks like other boundaries rotate with the fan.

Thanks for your help

[ping]

If you want surrounding features modelled like fan mountings and obsticals then you need two regions like the fan tutorial

But if you want just the fan and it all rotates then one region is fine

Then in dfbi only free the rotation dof eg the z axis

Best to start by adding dfbi to the fan tut

[chamounet]

hello

Thanks, i tried the DFBI on the fan model and it work properly, i will need to separate my fan region and create the interface to complete my simulation

thank you for your help.

[Alberto Damas]

Hello, I am simulating the same problem but I have some problems when I try to see the efect of wind. Do the DFBI allow to see the rotation? how can I do that?

Thanks.