question

Cecco · November 19, 2012, 13:12

Hi guys,
who can answer this question?
I'm simulating a centrifugal fun. I use to monitor the flow rate at the outlet of the system. If I look, by means of the "solver manager" of CFX, the graph concerning the flow rate I see oscillations. If I increase the total pressure (almost equal to static cause the flow is slow in that part) at the outlet this signal is more stable until a certain value of the pressure where I don't see oscillations and the signal is suddently stable. How can I interpret this?

ghorrocks · November 19, 2012, 17:53

The fan might be off its design point with the initial point, and increasing the pressure pushes it closer to an ideal operating point where the flow is simpler. This makes convergence easier.

November 19, 2012, 13:12	question	#1
Cecco Member Francesco Join Date: Jan 2012 Posts: 31 Rep Power: 14	Hi guys, who can answer this question? I'm simulating a centrifugal fun. I use to monitor the flow rate at the outlet of the system. If I look, by means of the "solver manager" of CFX, the graph concerning the flow rate I see oscillations. If I increase the total pressure (almost equal to static cause the flow is slow in that part) at the outlet this signal is more stable until a certain value of the pressure where I don't see oscillations and the signal is suddently stable. How can I interpret this?

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November 19, 2012, 17:53		#2
ghorrocks Super Moderator Glenn Horrocks Join Date: Mar 2009 Location: Sydney, Australia Posts: 17,872 Rep Power: 144	The fan might be off its design point with the initial point, and increasing the pressure pushes it closer to an ideal operating point where the flow is simpler. This makes convergence easier.