ANSYS FLUENT workbench fan setup

mariashva · November 4, 2017, 18:36

I have a question about fluent fan setup. I'm now working on a duct 40*40*100 with a pressure inlet and an exhaust fan outlet. I got a fan curve which is not linear. So I use excel to get the 5th order polynomial and put it in the fan pressure jump setup. I select turbulence model for simulation. When I run the simulation, it always shows x-momentum error, need to increase relaxation sweep. But when I changed from 0.7 to 0.5, the same error again. Then I changed the fan curve into a linear approximation, and keep the relaxation to be 0.7, it worked. So I'm not sure what was wrong when using the more accurate fan curve.
Anyone has a clue? Please help. Thanks.

mariashva · November 6, 2017, 13:24

Anyone can help? My understanding is that the higher order polynomial fan curve would trigger high inaccuracy when the fluid backflows along the curve. So I guess I need to restrict the flow speed within a reasonable range. But not sure how to do it in fluent.

November 4, 2017, 18:36	ANSYS FLUENT workbench fan setup	#1
mariashva New Member Ray Join Date: Mar 2014 Posts: 20 Rep Power: 12	I have a question about fluent fan setup. I'm now working on a duct 4040100 with a pressure inlet and an exhaust fan outlet. I got a fan curve which is not linear. So I use excel to get the 5th order polynomial and put it in the fan pressure jump setup. I select turbulence model for simulation. When I run the simulation, it always shows x-momentum error, need to increase relaxation sweep. But when I changed from 0.7 to 0.5, the same error again. Then I changed the fan curve into a linear approximation, and keep the relaxation to be 0.7, it worked. So I'm not sure what was wrong when using the more accurate fan curve. Anyone has a clue? Please help. Thanks.

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November 6, 2017, 13:24		#2
mariashva New Member Ray Join Date: Mar 2014 Posts: 20 Rep Power: 12	Anyone can help? My understanding is that the higher order polynomial fan curve would trigger high inaccuracy when the fluid backflows along the curve. So I guess I need to restrict the flow speed within a reasonable range. But not sure how to do it in fluent.