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juzer_700 May 18, 2012 06:45

Cold FLow analysis in Gas Turbine..Help Needed
I have been trying to use ANSYS FLUENT Software to simulate cold flow analysis inside a combustion chamber. But I am having difficulties. It shows reverse flow when I run the calculation. My geometry is in 2D-Axisymmetrical. Also I have taken a swirl facter of 0.7 using K-Epsilon RNG turbulence method.

Inlet condition:
Velocity- 1m/s, Air at 600K
Pressure Outlet - Gauge pressure=0

Is the reverse flow because I have included the swirl in the flow? Or is it because my domain is small?

I would really appreciate if you can help me figure out the problem. Thanks in advance.

jwillie2000 May 23, 2012 04:18

Hi, I think it is because of the swirl in the flow. I would suggest you activate the radial equilibrium pressure distribution option at the outlet and allow sufficient time for it to run and see whether the reverse flow would go away. Good luck! Jimmy

foamcfd May 23, 2012 05:18

It could be physical because of the swirl. Try extending your doamin at outlet. I won't worry if it's physical though.

juzer_700 May 23, 2012 06:28

@foamcd @jwillie2000

Thanks for replying

I extended the domain. And also activated the radial equilibrium pressure. Although the reversed flow has reduced, but there are still one or two points where it's occuring. I think it's physical as you pointed out.

JAY ADHVARYU August 17, 2013 11:11

How i get mean quatity plot in fluent like mean pressure plot, mean stremline plot etc.

jwillie2000 August 17, 2013 13:52


You have to monitored the quantities you are referring to. Normally u would do it in a plane if it is a 3D problem and you can take the area weighted average of the said quantity and then do the plot after. Are u running unsteady simulation? I would assume yes. In case you want to know what is happening along the centerline you can also export the data if you define your centerline. Once the data is exported as ASCII data you can do the plot using any plotting program.

You need to be more specific about what you want to do in case my post doesn't answer your question.

JAY ADHVARYU August 24, 2013 09:42

I have some problem with my boundary condition that how i utilize the neumann condition(∂φ/∂x = 0) at outlet. Can i select pressure outlet at outlet?
my inlet condition is :
flat velocity profile =40m/s
turbulent intensity=4.5%
And Inlet height of duct=5mm

I select velocity inlet at inlet because my flow is incompresible.
And axis boundary condition applied along the centerline.
and no slip condition at wall.

pls help me.

raymond350 September 10, 2013 05:03

Your inlet velocity is just 1m/s? If you increase it to say 30 or 40m/s i believe you will have lesser or no reverse flow.

JAY ADHVARYU September 30, 2013 02:47

yes, my flow is fully developed if you able to help pls help me as fast as possible because if i use pressure outlet at outlet i got reverse flow.

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