Rotating Squirrel Cage Fan

Stu12 · July 26, 2018, 18:53

Hello all.
I am relatively new to the CFX software. I was wondering I am attempting to run a simulation with a rotating fan.
I've tried simply putting the total fan geometry in a enclosure and setting it up a solid rotating domain in a fluid domain. No such luck.
I'm pretty green, please don't forget that. I am running it coupled with ansys 15.

Thanks,
Mr. Stu

ghorrocks · July 26, 2018, 21:04

It sounds like you are modelling the rotor as a solid domain. That is not correct. Please look at the CFX tutorial examples on rotating machinery as that will show you how to do it.

Stu12 · July 26, 2018, 21:44

Thanks a ton. Any one of the tutorials do you suggest? I don't have access to the turbo interface, I don't think.

Would immersed solid be more appropriate? This isn't anything like I remember from COMSOL. Lol

ghorrocks · July 26, 2018, 21:55

Any of the rotating machinery tutorials.

No, not immersed solids either

You don't model the solid at all, with any method. Look at the tutorials.

Stu12 · July 26, 2018, 21:57

Haha! Alrighty that's what I'll do.

Stu12 · July 27, 2018, 16:58

Alrighty, so I looked at a few of tutorials and took up the good fight once again!

Now, I have another issue: isolated fluid regions.

Here's the scenario:

I have placed my fan geometry inside a cylinder to outline it's rotational geometry, and placed that inside of a bigger cylinder !
I also cut 3/4 of it off for resource management. Alright, so, if the fan geometry is the crème in this oreo cookie, I have set up two frozen rotors for both of the chocolate cookies and the big encapsulating cylinder. Now, I am having issues with the crème to air interface. Any suggestions? I am using an opening boundary condition by the way. I have set the "fan" domain (fan geometry + fan blade span revolved) to rotate.

Thanks a lot!

Mr. Stu

ghorrocks · July 27, 2018, 20:44

As much as visualising oreo creme layers is useful an image would be better

The isolated fluid regions error means one or more of your interfaces are not connecting. You better check your interfaces.

Also post some images of what you are modelling and the output file.

Stu12 · July 31, 2018, 15:15

Thanks again for your help.

I am really unable to share any photos at this point. :/

I have tried simplifying it once again; created a cylindrical enclosure of my fan, and subtracted the fan while preserving the tool body.
Set up the fan as its own fluid domain and assigned wall boundary conditions to surfaces, and of course made the enclosure a fluid domain.

Thanks in advance.

July 26, 2018, 18:53	Rotating Squirrel Cage Fan	#1
Stu12 New Member Mr. Stuart Join Date: Jul 2018 Posts: 5 Rep Power: 8	Hello all. I am relatively new to the CFX software. I was wondering I am attempting to run a simulation with a rotating fan. I've tried simply putting the total fan geometry in a enclosure and setting it up a solid rotating domain in a fluid domain. No such luck. I'm pretty green, please don't forget that. I am running it coupled with ansys 15. Thanks, Mr. Stu

July 26, 2018, 21:04		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	It sounds like you are modelling the rotor as a solid domain. That is not correct. Please look at the CFX tutorial examples on rotating machinery as that will show you how to do it. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

July 26, 2018, 21:55		#4
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	Any of the rotating machinery tutorials. No, not immersed solids either You don't model the solid at all, with any method. Look at the tutorials. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

July 27, 2018, 20:44		#7
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,870 Rep Power: 144	As much as visualising oreo creme layers is useful an image would be better The isolated fluid regions error means one or more of your interfaces are not connecting. You better check your interfaces. Also post some images of what you are modelling and the output file. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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July 26, 2018, 21:44		#3
Stu12 New Member Mr. Stuart Join Date: Jul 2018 Posts: 5 Rep Power: 8	Thanks a ton. Any one of the tutorials do you suggest? I don't have access to the turbo interface, I don't think. Would immersed solid be more appropriate? This isn't anything like I remember from COMSOL. Lol

July 26, 2018, 21:57		#5
Stu12 New Member Mr. Stuart Join Date: Jul 2018 Posts: 5 Rep Power: 8	Haha! Alrighty that's what I'll do.

July 27, 2018, 16:58		#6
Stu12 New Member Mr. Stuart Join Date: Jul 2018 Posts: 5 Rep Power: 8	Alrighty, so I looked at a few of tutorials and took up the good fight once again! Now, I have another issue: isolated fluid regions. Here's the scenario: I have placed my fan geometry inside a cylinder to outline it's rotational geometry, and placed that inside of a bigger cylinder ! I also cut 3/4 of it off for resource management. Alright, so, if the fan geometry is the crème in this oreo cookie, I have set up two frozen rotors for both of the chocolate cookies and the big encapsulating cylinder. Now, I am having issues with the crème to air interface. Any suggestions? I am using an opening boundary condition by the way. I have set the "fan" domain (fan geometry + fan blade span revolved) to rotate. Thanks a lot! Mr. Stu

July 31, 2018, 15:15		#8
Stu12 New Member Mr. Stuart Join Date: Jul 2018 Posts: 5 Rep Power: 8	Thanks again for your help. I am really unable to share any photos at this point. :/ I have tried simplifying it once again; created a cylindrical enclosure of my fan, and subtracted the fan while preserving the tool body. Set up the fan as its own fluid domain and assigned wall boundary conditions to surfaces, and of course made the enclosure a fluid domain. Thanks in advance.