need hep

rahulv · August 22, 2010, 00:42

Hi all, I am new to cfd/cfx. I am trying to model the flow in an axial fan with 5 blades which is just meant for pushing the air and should give small pressure rise.

I have made the fluid volume but cannot understand what b.c combination to apply in CFX.

I know only inlet atmospheric pressure and rpm. I don't know outlet pressure and mass flow rate, which i am trying to find out.

How to do this. Please let me know. Thank you

Josh · August 24, 2010, 20:47

Hi Rahul -

You shouldn't need to use an outlet mass flow rate if you're using an inlet mass flow rate. You should probably use an outlet pressure. You can determine it with experimental results. If those aren't available, I've used a far downstream outlet with the pressure equal to the atmospheric pressure. It's not perfect, but it worked in my case.

rahulv · August 25, 2010, 04:36

thx for the help

CCTech_Pune · August 25, 2010, 08:44

Hi

Use

Inlet BC = Total pressure
Outlet BC = Static Pressure

Accordingly choose operating pressure.

Thanks
CCTech Pune

August 22, 2010, 00:42	need hep	#1
rahulv Member Rahul Vaibhav Join Date: Nov 2009 Location: India Posts: 33 Rep Power: 17	Hi all, I am new to cfd/cfx. I am trying to model the flow in an axial fan with 5 blades which is just meant for pushing the air and should give small pressure rise. I have made the fluid volume but cannot understand what b.c combination to apply in CFX. I know only inlet atmospheric pressure and rpm. I don't know outlet pressure and mass flow rate, which i am trying to find out. How to do this. Please let me know. Thank you

August 25, 2010, 04:36	cfd	#3
rahulv Member Rahul Vaibhav Join Date: Nov 2009 Location: India Posts: 33 Rep Power: 17	thx for the help

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August 24, 2010, 20:47		#2
Josh Senior Member Joshua Counsil Join Date: Jul 2009 Location: Halifax, Nova Scotia, Canada Posts: 366 Rep Power: 18	Hi Rahul - You shouldn't need to use an outlet mass flow rate if you're using an inlet mass flow rate. You should probably use an outlet pressure. You can determine it with experimental results. If those aren't available, I've used a far downstream outlet with the pressure equal to the atmospheric pressure. It's not perfect, but it worked in my case.

August 25, 2010, 08:44		#4
CCTech_Pune New Member CCTech Join Date: Jul 2010 Posts: 20 Rep Power: 16	Hi Use Inlet BC = Total pressure Outlet BC = Static Pressure Accordingly choose operating pressure. Thanks CCTech Pune