[wadoud31]

hi
I want to study the flow in radial turbine why I used icem cfd for the creation of geometry, I have three domains the first is volute the second is the distributor (21 blades) and the last is the rotor (11 blades) but I took only one passage in the distributor and the rotor (see picture), but after 400 ittérations I have error:
| ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Stopped in routine FPX: C_FPX_HANDLER
ERROR #001100279 has occurred in subroutine ErrAction. |
| Message: |
| Floating point exception: Overflow
the question is:
how I should definire interface between volute and distributor and the interface between distributor and rotor

[Far]

http://www.ansys.com/staticassets/AN...utchinson1.pdf

[ghorrocks]

And this FAQ might help: http://www.cfd-online.com/Wiki/Ansys...do_about_it.3F

[wadoud31]

thank you my friends

[wadoud31]

hi
thank you for reply i will read it
best regards

[wadoud31]

hi
I have questions about icem pre (14.5):
- How to define the value of pitch change angle ?
- how I can make a simulation in unsteady state and the geometry can change shape? in this case the angle of the turn of the airfoils distributor changes with pressure at inlet?
thank you my friends

[ghorrocks]

Which pitch do you want to change?

To change shape you need moving mesh or if it is just rotation you can do it with rotating frame of reference.

[wadoud31]

thank you for reply
for pitch change angle
I have 15 airfoils for the distributor and 11 of the rotor is that the pitch change angle value: 360/15 for distributor and 360/11 for the rotor?
the second question is: I want to simulate the flow in a turbocharger with vanned nozzle with a pulsed flow:
when the pressure at the inlet is 3 bar the angle of airfoils of the distributor is 15 ° and when the pressure at the inlet is 2 bar the angle of airfoils of the distributor is 11° in unsteady state simulation the pressure changes how i can change the angle of the airfoil automatically in the simulation?

[wadoud31]

HI my friends
I think I do not manage my question correctly, if you want me to bring more precision I would be available;
how i can move the mesh of the distributor during the simulation in unsteady case ?
thank you

[ghorrocks]

How can you change the angle of attack? Does the blade move or is this change in AOA due to the different flow conditions and the blade stays in the same position?

[wadoud31]

hi




thank you for reply
for each total pressure at the inlet there is a precise position of the blade in order to increase the efficiency of the turbine for each diet, so the blade moves according to the conditions of the turbine inlet: I did of simultations as follows:
when the pressure of 3 bar the position of the blade is 19 °
when the pressure of 2 bar the position of the blade is 15 °
when the pressure of 1.5 bar the position of the blade is 13 °
Now I want to make a single simulation which includes three precidentes simulteions with inlet pressure that varies between 3; 2 and 1.5 bar.
the question is:
-how to define the boundary conditions (total pressure at the inlet) which varies between three values ​​(I think I must use unsteady)?
-how to vary the posiont of the blade automatically for each pressure (geometry) and how the mesh follows the position of the blade?
thank you
best regards

[ghorrocks]

Before you go too far I would check whether you can use moving mesh on a rotating frame of reference. If you cannot use moving mesh to change the blade AOA then I cannot see how you are going to do this simulation in CFX.

Why do you need to have 3 AOA in one simulation? This simulation is easy if it is done as 3 separate simulations at each blade position. You are making things MUCH harder for yourself by moving the AOA.

[wadoud31]

hi
Thanks for the reply
I want to study the behavior of the turbine when changing conditions at the inlet in unsteady state.
I need to know is that ANSYS is able to do this simulation?
I want to know how to use a moving mesh of a rotating frame?
thank you.

best regards.

[enuano]

Hello!
I'm simulating a turbine without volute. THe pitch angle is, like you say, 360/#blades, in my case, the stator has 11 blades and the rotor 12, so if I want to study just a portion, I put 360/11 and 360/12.




- Interface Type
Fluid to fluid
- Interface Models option
For the interface between stator and rotor, the interface models option is set to General Connection, because they connect non-matching grids.

- Mesh Connection
The mesh connection selected is GGI (General Grid Interface). That option is necessary when the grid on either side of the two connected surfaces does not match.

I hope it helps

[wadoud31]

hi
thank you for reply gato.
I already did that but after 430 itterations the solution diverged. so I took the full rotor.
the problem is how to simulate the flow in the turbine with the movement of the nozzle vanes.
best regards