Modelling a rotary bucket

xsw23edc · November 26, 2014, 17:16

Hi everyone, this is my first thread!! I'm trying to modelling a conic shape rotary bucket. I need to find how fast the fluid exit from a hole in the wall.

This id the 2D geometry I made with Gambit:

The upper edge is the fluid inlet section (mass flow b.c.), the nozzle is the fluid outlet section (pressure outlet b.c.) and the conic shape is the rotating part of the system. Now my problem is how to set the b.c. for the fluid and the moving wall.
For the wall I chose moving wall->rotational

now I don't know how set the y-axis as the rotating axis and what's the difference between 'Relative..' and 'Absolute'.

Then I don't know what kind of motion select for the fluid phase.

I tried different combination between wall and fluid b.c. but all the results seems to be incorrect.
Hope someone can help me! Thanks for your time.

xsw23edc · December 2, 2014, 10:50

No one who can help me?

pakk · December 2, 2014, 11:31

I know how to do it in 3D. Then the "wall condition" screen shows "Rotation-axis direction", where you can set the axis direction. I am surprised that this is not showing in the 2D axisymmetric version, which I assume you are using.

For the fluent phase (I think you mean what Fluent calls "cell zone"), you should not specify any rotation, at least not in 3D. It will be automatically induced by the boundary conditions, just let Fluent find out that the fluid rotates.

November 26, 2014, 17:16	Modelling a rotary bucket	#1
xsw23edc New Member Gilb Join Date: Nov 2014 Posts: 2 Rep Power: 0	Hi everyone, this is my first thread!! I'm trying to modelling a conic shape rotary bucket. I need to find how fast the fluid exit from a hole in the wall. This id the 2D geometry I made with Gambit: The upper edge is the fluid inlet section (mass flow b.c.), the nozzle is the fluid outlet section (pressure outlet b.c.) and the conic shape is the rotating part of the system. Now my problem is how to set the b.c. for the fluid and the moving wall. For the wall I chose moving wall->rotational now I don't know how set the y-axis as the rotating axis and what's the difference between 'Relative..' and 'Absolute'. Then I don't know what kind of motion select for the fluid phase. I tried different combination between wall and fluid b.c. but all the results seems to be incorrect. Hope someone can help me! Thanks for your time.

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December 2, 2014, 10:50		#2
xsw23edc New Member Gilb Join Date: Nov 2014 Posts: 2 Rep Power: 0	No one who can help me?

December 2, 2014, 11:31		#3
pakk Senior Member Join Date: Nov 2013 Posts: 1,965 Rep Power: 26	I know how to do it in 3D. Then the "wall condition" screen shows "Rotation-axis direction", where you can set the axis direction. I am surprised that this is not showing in the 2D axisymmetric version, which I assume you are using. For the fluent phase (I think you mean what Fluent calls "cell zone"), you should not specify any rotation, at least not in 3D. It will be automatically induced by the boundary conditions, just let Fluent find out that the fluid rotates.