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-   -   moving mesh in cfx (http://www.cfd-online.com/Forums/cfx/23689-moving-mesh-cfx.html)

eleazar solve everything February 28, 2007 08:16

moving mesh in cfx
 
hello forum

first of all i am most structural than cfd engineer , but these days i have to work also in cfd because one on the engineers in my company leave ... well we have a software called cfx and i want to make a simulation of a valve to see the flow as the valve opens and close , can you please tell me where can i find some info how to do this??? the help file of the software in not to good!! i make the water part mesh in a icem cfd anf export it as a file to cfx now i open it in cfx and then i do not know how to make the valve move...... (the mesh has also the water and the valve) ..

best regards eleazar

Glenn Horrocks February 28, 2007 17:18

Re: moving mesh in cfx
 
Hi,

What sort of valve?

If you are new to CFD modelling then this is not a good problem to start with. I recommend working through some of the tutorials with CFX first.

Glenn Horrocks

eleazar solve everything February 28, 2007 19:26

Re: moving mesh in cfx
 
this is a good advise.....

i want to simulate an internal compusion engine to see the flow when the input valve open and when it close after the piston movement.... do you know any familiar tutorial to see..

i saw your work.... you are every good

best regards

Glenn Horrocks March 1, 2007 17:15

Re: moving mesh in cfx
 
Hi,

No tutorials exist for modelling moving valves in CFX to my knowledge. I assume you are referring to my PhD thesis where I modelled a rotary valve engine in CFX4 - this model is easily done in CFX5 using GGIs and a rotating frame of reference. Poppet valves are significantly harder and require some combination of moving mesh with GGI's or remeshing with interpolation to a new mesh.

Not easy stuff to do by any means. Make sure you are quite familiar with CFX and how to get accurate simulations before you attempt this. That's why I recommend you start with easy stuff.

Glenn Horrocks

G March 2, 2007 06:27

Re: moving mesh in cfx
 
Hi,

try to learn something from the first part of the tutorial 20 - mesh deformation.

I can send you a test .cfx file, which I made, where I modelled only movement of an exhaust valve (without the cylinder and inlet valve). You can learn there what should you prescribe on boundaries.


M.Emara March 6, 2007 02:41

Re: moving mesh in cfx
 
hello everybody :)

I found this nice forum while surfing through the net. I'm stuck in such problem.I'm trying to simulate an In- cylinder flow in a diesel engine with cfx. The only tutorial with moving mesh was the one with fluid structure interaction. I will make several steady simulations with different valve and pistons lifts and then I can animte the results . but this not a good solution because the times must be considered in the relation of the piston and valve lifts. other thing to simplify the problem, I didn't simulate the injection or the combusation and I used just Air (ideal Gas) as fluid. After I have worked out the tutorial with moving mesh i tried make my own model moving... but withour any success .. even a simple piston movement doesn't work :( If you send your test.cfx file , or if anybody give tipps I will be very greatful. (even with a simple modell just like a cylinder with top as inlet, wall as wall and bottom(piston) as moving wall)??? !!!!! :(

thanks a lot and sorry for the long text :)


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