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gilberto October 1, 2001 12:53

Rotor in pipe.
Hi, everyone,

Well, I am designing a rotor,and this rotor is in a pipe,and the problem is the pipe has a bend before the rotor. To clarify the stuff, just imagineit in a simple way, a vertically upwards pipe,then a turning of 90 degrees, another piece of pipe(horizontal), and then the rotor inside the pipe, and after the rotor, another bend of 90 degrees, and a downwards facing pipe,ok?You get the idea?

The main problem is putting this stuff to rotate. I I create a rotating frame of reference, how do I keep the rest of the things stationary and the rotor running at a specified speed???Well, if I do this thing about defining your other surfaces as counter-rotating, am I not going to have any problems???How do the boundary conditions change if your frame is rotating?I did some tests and I am getting funny results, because, as I set the rest of the surfaces to counter-rotate,this counter rotation influences the flow prior to the rotor, and I clearly do not want that.

Well, hope you can give me some hints, if you had a probelm like mine before,thanks,


Robin Steed October 1, 2001 17:02

Re: Rotor in pipe.
Hi Gilberto,

The answer depends on which code you are using. Are you running CFX-TASCflow, CFX-4, or CFX-5?


gilberto October 2, 2001 04:38

Re: Rotor in pipe.
Hi Robin,

I am using CFX-5.5. Can you help me with some hints, mate?


gilberto October 2, 2001 04:39

Re: Rotor in pipe.
Sorry, i got confused by the following messages,hahahaha, I am using CFX-5.4.1. I thik CFX5.5 has not even come up yet, it would be pretty impossible to be using that now, don't you think?

Robin Steed October 2, 2001 08:36

Re: Rotor in pipe.
Hi Gilberto,

I'm afraid you will have to wait a few weeks to do this one. CFX-5.4.1 cannot model Multiple Frames of Reference (MFR). This capability has been added to CFX-5.5 (and works very well), which is due out later this month.

With CFX-5.5 you can create separate grids for your inlet pipe, rotor, and outlet pipe. These grids may be combined using General Grid Interfaces (GGI), thus allowing a frame change. Each domain may be specified with a corresponding frame of reference (stationary or rotating). The interface does the rest.

Best regards, Robin

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