Axial Flow Fan Performance Map

petrosdd · February 19, 2021, 04:04

Hello everyone, I have simulated an axial flow fan in CFX, and I'm trying to get the performance map for that fan (4 or 5 curves). So I need to run multiple cases for each curve (constant rotational speed) and either change the mass flow rate, or the pressure difference. Since changing the mass flow rate is a more secure option than changing the outlet pressure in order to get the ΔP (that would require guessing and maybe the map will not be correct), I'm going with mass flow outlet BC.

My question is, how do I change the mass flow rate for constant rpm since the setup has a constant cross section area, constant density (it's a small scale low speed fan) and each fan draws constant mass flow (hence axial velocity) for constant rpm.

Thank you in advance.

Opaque · February 19, 2021, 07:32

What release version are you currently using?

petrosdd · February 19, 2021, 08:46

Quote:

Originally Posted by Opaque

What release version are you currently using?

I'm using 19.4

Opaque · February 19, 2021, 09:22

The creation of performance maps is a recent feature, and reduces the pain of generating them. My advice is to upgrade to a more recent version, 2020Rx, or 2021R1

Using the feature, you only need to specify the range of the variables of interest, say

mass flow = 0.1, 0.3, 0.5 [kg/s]
rpm = 5000, 5500, 6000 [rpm]
... = ... [ ]

and submit the simulation. Once finished, you can open the results file in CFD-Post and look at the performance map directly, including the different speed lines, and contours

petrosdd · February 19, 2021, 11:42

Quote:

Originally Posted by Opaque

The creation of performance maps is a recent feature, and reduces the pain of generating them. My advice is to upgrade to a more recent version, 2020Rx, or 2021R1

Using the feature, you only need to specify the range of the variables of interest, say

mass flow = 0.1, 0.3, 0.5 [kg/s]
rpm = 5000, 5500, 6000 [rpm]
... = ... [ ]

and submit the simulation. Once finished, you can open the results file in CFD-Post and look at the performance map directly, including the different speed lines, and contours

Ok I will try your suggestion. Thank you.

Opaque · February 19, 2021, 15:22

https://www.ansys.com/products/fluids/ansys-cfx

February 19, 2021, 04:04	Axial Flow Fan Performance Map	#1
petrosdd New Member Zero Join Date: May 2020 Posts: 12 Rep Power: 6	Hello everyone, I have simulated an axial flow fan in CFX, and I'm trying to get the performance map for that fan (4 or 5 curves). So I need to run multiple cases for each curve (constant rotational speed) and either change the mass flow rate, or the pressure difference. Since changing the mass flow rate is a more secure option than changing the outlet pressure in order to get the ΔP (that would require guessing and maybe the map will not be correct), I'm going with mass flow outlet BC. My question is, how do I change the mass flow rate for constant rpm since the setup has a constant cross section area, constant density (it's a small scale low speed fan) and each fan draws constant mass flow (hence axial velocity) for constant rpm. Thank you in advance.

February 19, 2021, 07:32		#2
Opaque Senior Member Join Date: Jun 2009 Posts: 1,819 Rep Power: 32	What release version are you currently using? __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

February 19, 2021, 09:22		#4
Opaque Senior Member Join Date: Jun 2009 Posts: 1,819 Rep Power: 32	The creation of performance maps is a recent feature, and reduces the pain of generating them. My advice is to upgrade to a more recent version, 2020Rx, or 2021R1 Using the feature, you only need to specify the range of the variables of interest, say mass flow = 0.1, 0.3, 0.5 [kg/s] rpm = 5000, 5500, 6000 [rpm] ... = ... [ ] and submit the simulation. Once finished, you can open the results file in CFD-Post and look at the performance map directly, including the different speed lines, and contours aero_head likes this. __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

February 19, 2021, 15:22		#6
Opaque Senior Member Join Date: Jun 2009 Posts: 1,819 Rep Power: 32	https://www.ansys.com/products/fluids/ansys-cfx __________________ Note: I do not answer CFD questions by PM. CFD questions should be posted on the forum.

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