Axial Flow Fan

mawais15 · December 19, 2010, 23:35

I wonder if there is a mathematical formula to calculate the flow rate of a fan if following parameter are known

Fan effective diameters
Blade Angle ( Pitch )
Number of Blades
Speed ( RPM )
Power Consumption
Pressure at inlet of the fan

Regards

Hamidzoka · December 20, 2010, 01:31

there are some empirical ralations for such this calculations.
but they are limited to some specific geometries and their application is limited.

regards

mawais15 · December 20, 2010, 01:38

i have measured the basic dimension and geometrical equation of the fan that i am going got measure the flow rate of.
but i don't know the relations. :-(

mawais15 · December 20, 2010, 01:39

why are you saying that its application is limited?

Hamidzoka · December 20, 2010, 02:01

there are some coefficients for these relations which are function of blade geometry as well as type of the flow. they are usually available just for some limited fan blade shapes and flow types.

regards

mawais15 · December 20, 2010, 06:07

Oh i c...!!

urmilshah · May 26, 2011, 04:05

hey,

I am working on the design of a low pressure axial flow fan.

I have generated the aerofoil sections at 5 different radii of the fan
along with their stagger angles. What I am struggling with is how they are
to be oriented with respect to each other in the axial direction. For a
aerofoil at a given radii, I have found its its stagger angle. But, I
could still translate it along the circumference (i.e. sweep) and along
the axis of the fan.

I am unable to decide how to move the sections along the axial direction,
before I pass a best fit surface through them to generate a fan blade.
Also does anyone have any idea on how to decide on sweep angle ?

mawais15 · May 26, 2011, 08:42

Quote:

Originally Posted by urmilshah

hey,

I am working on the design of a low pressure axial flow fan.

I have generated the aerofoil sections at 5 different radii of the fan
along with their stagger angles. What I am struggling with is how they are
to be oriented with respect to each other in the axial direction. For a
aerofoil at a given radii, I have found its its stagger angle. But, I
could still translate it along the circumference (i.e. sweep) and along
the axis of the fan.

I am unable to decide how to move the sections along the axial direction,
before I pass a best fit surface through them to generate a fan blade.
Also does anyone have any idea on how to decide on sweep angle ?

what softwares u r using??

any image will be helpful

December 19, 2010, 23:35	Axial Flow Fan	#1
mawais15 New Member SCORPION Join Date: Dec 2010 Location: Pakistan Posts: 5 Rep Power: 15	I wonder if there is a mathematical formula to calculate the flow rate of a fan if following parameter are known Fan effective diameters Blade Angle ( Pitch ) Number of Blades Speed ( RPM ) Power Consumption Pressure at inlet of the fan Regards

May 26, 2011, 04:05	uss	#7
urmilshah New Member Urmil Shah Join Date: May 2011 Posts: 1 Rep Power: 0	hey, I am working on the design of a low pressure axial flow fan. I have generated the aerofoil sections at 5 different radii of the fan along with their stagger angles. What I am struggling with is how they are to be oriented with respect to each other in the axial direction. For a aerofoil at a given radii, I have found its its stagger angle. But, I could still translate it along the circumference (i.e. sweep) and along the axis of the fan. I am unable to decide how to move the sections along the axial direction, before I pass a best fit surface through them to generate a fan blade. Also does anyone have any idea on how to decide on sweep angle ?

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December 20, 2010, 01:31		#2
Hamidzoka Senior Member Hamid Zoka Join Date: Nov 2009 Posts: 282 Rep Power: 18	there are some empirical ralations for such this calculations. but they are limited to some specific geometries and their application is limited. regards

December 20, 2010, 01:38		#3
mawais15 New Member SCORPION Join Date: Dec 2010 Location: Pakistan Posts: 5 Rep Power: 15	i have measured the basic dimension and geometrical equation of the fan that i am going got measure the flow rate of. but i don't know the relations. :-(

December 20, 2010, 01:39		#4
mawais15 New Member SCORPION Join Date: Dec 2010 Location: Pakistan Posts: 5 Rep Power: 15	why are you saying that its application is limited?

December 20, 2010, 02:01		#5
Hamidzoka Senior Member Hamid Zoka Join Date: Nov 2009 Posts: 282 Rep Power: 18	there are some coefficients for these relations which are function of blade geometry as well as type of the flow. they are usually available just for some limited fan blade shapes and flow types. regards

December 20, 2010, 06:07		#6
mawais15 New Member SCORPION Join Date: Dec 2010 Location: Pakistan Posts: 5 Rep Power: 15	Oh i c...!!