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-   -   Cylindrical Components Boundary Conditions (http://www.cfd-online.com/Forums/cfx/121936-cylindrical-components-boundary-conditions.html)

magnusDux85 August 8, 2013 07:02

Cylindrical Components Boundary Conditions
 
Do somebody can give clear instruction how understand cylindrical components from ANSYS point of view? Are they unit vectors or what?

I want to mimic swirling flow in injector of combustion chamber.

ghorrocks August 8, 2013 08:03

I do not understand what you are asking. Cylindrical coords for what? A local coord system? Or a 2D axisymmetric simulation? And what are you modelling in your injector - the flow inside the injector, the spray it creates or a combustion model?

magnusDux85 August 8, 2013 08:06

Cylindrical comp. of flow direction as a result I want to have fuel well mixed with oxygen.

ghorrocks August 8, 2013 08:09

I still do not understand what you are asking. Have you completed a simulation and you want to extract the velocity of something in cylindrical corrds? If so what is something?

magnusDux85 August 8, 2013 08:14

Please have a look:

http://postimg.org/image/4rqo0p3dt/ injector is modeled in this case as a point source...

ghorrocks August 8, 2013 08:20

I assume you are asking what form the cylindrical coords are. Yes, they are unit vectors. But I think you can enter any vector and CFX will take them as unit vectors anyway.

magnusDux85 August 8, 2013 08:24

You are right, I was asking about it thx.

magnusDux85 August 8, 2013 08:32

But how check influence of these components on swirling properties in the simplest way?

magnusDux85 August 8, 2013 13:38

Very difficult to predict :(.

magnusDux85 August 8, 2013 14:16

To do the topic more understandable I have attached image:

http://postimg.org/image/hj4w0kz45/

ghorrocks August 8, 2013 18:47

Your image was not attached and your question is still not clear.

But if you are asking how can you assess the importance of the direction vector on your simulation - you can do this with a simple sensitivity analysis. Just run a series of simulations with different direction vectors and compare the results. If there is no significant change in the result then the direction vector makes little difference.

magnusDux85 August 9, 2013 02:45

Quote:

Originally Posted by ghorrocks (Post 444645)
Your image was not attached and your question is still not clear.

But if you are asking how can you assess the importance of the direction vector on your simulation - you can do this with a simple sensitivity analysis. Just run a series of simulations with different direction vectors and compare the results. If there is no significant change in the result then the direction vector makes little difference.

Thank you know it is: http://postimg.org/image/hj4w0kz45/

mirabella August 11, 2013 18:26

swirl modeling
 
Hello

I am facing the same issue. I want to generate a certain swirl in an axisymmetric slice section of a burner chamber. The question is then here, how is the flow direction related to the swirl strength and to the flow pattern?
Therefore, I need first of all to know the exact definition of theta component?


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