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CFD rotating machinery solving error
Posted 30 juin 2011, 14:33 UTC−4 3 Replies
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Hi all,
I'm working with the rotating machinery and am having trouble doing simple things. I always receive the error "Failed to find consistent initial values. Last time step is not converged." as the study starts. Please let me know if you are having the same problem or if you have a solution. I've attached my model.
Thank you!
I'm working with the rotating machinery and am having trouble doing simple things. I always receive the error "Failed to find consistent initial values. Last time step is not converged." as the study starts. Please let me know if you are having the same problem or if you have a solution. I've attached my model.
Thank you!
Attachments:
3 Replies Last Post 4 juil. 2011, 03:30 UTC−4
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Posted:
1 decade ago
Hi,
In you model there are several issues. First of all the way you defined the geometry is wrong. You need to subtract the rotating part from the fixed part and create an assembly, you had better to study the manual and the example of the baffled stirred mixer.
Then you will need to define a function to allow for your boundary conditions to start from zero and smoothly grow to the desired value.
Cheers
In you model there are several issues. First of all the way you defined the geometry is wrong. You need to subtract the rotating part from the fixed part and create an assembly, you had better to study the manual and the example of the baffled stirred mixer.
Then you will need to define a function to allow for your boundary conditions to start from zero and smoothly grow to the desired value.
Cheers
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Posted:
1 decade ago
Hi Amir,
Thank you for your advice. I fixed some parts of the model, and now it compiles and solves. I subtracted the circle from the square and defined an assembly, but to be able to create a rotating boundary I needed to put in another circle. Unfortunately, this is not what I want. It looks like the inside is rotating (which I'd rather have stationary), but the outside is stationary, and that part needs to rotate. How should I change this?
Thanks!
p.s. I've attached the new model
Thank you for your advice. I fixed some parts of the model, and now it compiles and solves. I subtracted the circle from the square and defined an assembly, but to be able to create a rotating boundary I needed to put in another circle. Unfortunately, this is not what I want. It looks like the inside is rotating (which I'd rather have stationary), but the outside is stationary, and that part needs to rotate. How should I change this?
Thanks!
p.s. I've attached the new model
Attachments:
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Posted:
1 decade ago
Hi,
I am not sure I follow you. You have a rectangular box, and inside there is a cylinder that rotates; in order to have an assembly you need to have an intermediate cylinder that you label as 'Rotating domain' then you define an identity pair that allows for flwo continuity along the inner boundary of the intermediate cylinder, thus the inner and intermediate cylinders rotate whereas the rectangular box appears to be still while inside of it the fluid (air) is actually subject to vortexes. What I see is that you did not define the itnermediate cylinder thus you did not define the identity pair.
Please find attached a revised version of your model. Please note that to speed things up I reduced your rotational speed from 1round/s to 0.75round/s.
Cheers
I am not sure I follow you. You have a rectangular box, and inside there is a cylinder that rotates; in order to have an assembly you need to have an intermediate cylinder that you label as 'Rotating domain' then you define an identity pair that allows for flwo continuity along the inner boundary of the intermediate cylinder, thus the inner and intermediate cylinders rotate whereas the rectangular box appears to be still while inside of it the fluid (air) is actually subject to vortexes. What I see is that you did not define the itnermediate cylinder thus you did not define the identity pair.
Please find attached a revised version of your model. Please note that to speed things up I reduced your rotational speed from 1round/s to 0.75round/s.
Cheers
Attachments: