CR4 - The Engineer's Place for News and Discussion®

Previous in Forum: Eng Robert Bruce   Next in Forum: What is the Rule/Standard for Adding a Reinforced Pad for Pipe Support?
Close

Comments Format:






Close

Subscribe to Discussion:

CR4 allows you to "subscribe" to a discussion
so that you can be notified of new comments to
the discussion via email.

Close

Rating Vote:







7 comments
Participant

Join Date: Jan 2012
Posts: 2

Centrifugal Blower CFM: How To Calculate

01/25/2012 12:24 PM

Blower fan Dia 600mm,

Blower fan wigth 80mm ,

Blower fan suction area 210mm,

Blower fan number of blade 12 nos,

Blower outer cover 117mm wigdh,

Blower outer cover dia 810mm,

Blower outer cover suction area 210mm,

Blower air out area 177x177x177x177mm

Power 15hp , 2880 RPM

How much for out air cfm , pls sombody help me and how to calculate formula

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Guru
Hobbies - Automotive Performance - New Member Popular Science - Weaponology - New Member

Join Date: Oct 2008
Location: Want to be: 34° 34' 21.60" N, 92° 55' 42.28" W Really am in Arizona
Posts: 30133
Good Answers: 1139
#1

Re: centrifugal blower cfm how to calculate

01/25/2012 12:27 PM

Why not ask the manufacturer?

Or, is this homework?

And don't you think that the shape/angle/form of the blades might be improtant, too?????

As a last resort:

UEI DAFM3 Digital Air Flow Meter$10

__________________
Luck comes and goes. Skill is forever. The supply of fools will always outstrip the demand .
Register to Reply
Participant

Join Date: Jan 2012
Posts: 2
#3
In reply to #1

Re: centrifugal blower cfm how to calculate

01/25/2012 12:37 PM

fan degree 35 , fan shape flat and straight , i am a manufacturer for textile machines , i was buy fan from one small company but this is custamised design they dont no perfect calculation , digital meter to buy but i want to improve nolage to manualy thats why i am asking calculation formula if you know pls tell me

Register to Reply Off Topic (Score 5)
Guru
Hobbies - Fishing - Old Salt Hobbies - CNC - New Member United States - US - Statue of Liberty - New Member

Join Date: Mar 2007
Location: Rosedale, Maryland USA
Posts: 4682
Good Answers: 232
#6
In reply to #3

Re: centrifugal blower cfm how to calculate

01/26/2012 8:21 AM

There is no ideal formula to give exact CFM for a blower. There are too many variables that fall into place in the mechanical construction to deal with. Example is you give the pitch at 35 degrees. So if the impeller has the blades welded on each blade may not be exactly 35 degrees. Close but not exact, so each impeller would preform a little different. Another is the clearances. You have to allow for some tolerances in fabrication. That is why company did was not able to give an exact CFM output. Also the name plate rpm on the motor. It is only a rating maybe different in application. The only way is to test it. They do test them just not every one this gives them an idea what their average losses are. Which they can then figure into a formula.

If you want a general formula of ideally what the the blower CFM should be volume of the housing times RPM of the motor.

__________________
Life is not a journey to the grave with the intention of arriving in a pretty, pristine body but rather to come sliding in sideways, all used up and exclaiming, "Wow, what a ride!"
Register to Reply Off Topic (Score 5)
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 9903
Good Answers: 542
#2

Re: centrifugal blower cfm how to calculate

01/25/2012 12:34 PM
__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply
Guru

Join Date: Mar 2007
Location: at the beach in Florida
Posts: 9903
Good Answers: 542
#4
In reply to #2

Re: centrifugal blower cfm how to calculate

01/25/2012 1:03 PM

You can estimate cfm by using hp...

HP =Volume (cfm) x Pressure (lb. Per sq. in.)

229 x Mechanical Efficiency of Fan

For purpose of estimating, the eff. of a fan or blower may be assumed to be 0.65.

Note:Air Capacity (cfm) varies directly with fan speed. Developed Pressure varies with square of fan speed. Hp varies with cube of fan speed.
__________________
Life is like riding a bicycle. To keep your balance you must keep moving. A.E.
Register to Reply Score 1 for Good Answer
Guru

Join Date: Jul 2005
Location: Stoke-on-Trent, UK
Posts: 2491
Good Answers: 70
#5

Re: Centrifugal Blower CFM: How To Calculate

01/25/2012 2:36 PM

I like the one-dimensional suction port and the 4-dimensional discharge!

__________________
Give masochists a fair crack of the whip
Register to Reply Off Topic (Score 4)
Associate

Join Date: Feb 2012
Posts: 37
#7

Re: Centrifugal Blower CFM: How To Calculate

02/21/2012 12:16 AM

Centrifugal Fans and Blowers typically have one of seven types of wheels that draw the air into the inlet of the blower housing, through the wheel, and discharges it at 90 degrees out through the discharge of the housing.

Register to Reply
Register to Reply 7 comments
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Comments rated to be "almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, rate them!
Copy to Clipboard

Users who posted comments:

Codemaster (1); karthikbmw (1); lyn (1); MarkhamCornoit (1); ozzb (1); SolarEagle (2)

Previous in Forum: Eng Robert Bruce   Next in Forum: What is the Rule/Standard for Adding a Reinforced Pad for Pipe Support?

Advertisement