| Author | Message | ||
| Ralph Peters (Ralph7)
Registered Member Username: Ralph7 Post Number: 147 Registered: 3-2004 Posted From: 75.195.133.48 Rating: N/A |
How to figure approx. CFM of a fan? Mainly electric under 20in. diameter. | ||
| john w. roan (Chessie4905)
Registered Member Username: Chessie4905 Post Number: 1967 Registered: 10-2003 Posted From: 71.58.71.157  Rating: N/A |
go to any site that sells electric cooling fans for motor vehicles. They list cfm for various sized fans hey sell | ||
| Kyle Brandt (Kyle4501)
Registered Member Username: Kyle4501 Post Number: 614 Registered: 9-2004 Posted From: 65.23.106.193  Rating: N/A |
You need to get the fan performance curve (it shows the CFM vs pressure drop related to required HP. Listings of CFM without the pressure drop is absolutely useless. (like giving the final score of only 1 of the teams.) CFM at 0 pressure drop is nearly meaningless, unless you are moving air in a room, then it won't matter. However, if you are moving air thru a radiator - you will have a significant pressure drop, so actual air moved under those conditions is what is whats going to matter. (Even the fans used on your home central AC have performance curves.) There are different fan blade designs depending on the application. Different efficiencies depending on the back pressure. What are you needing the fan for? | ||
| Tom Christman (Tchristman)
Registered Member Username: Tchristman Post Number: 256 Registered: 1-2006 Posted From: 66.218.33.156 Rating: N/A |
There are so many factors that affect CFM output in a blade fan. How many blades, how are the blades shaped, how much pitch on the blades, metal or composite that can flex, what speed. Just have to go to the fan manufacturers site and figure out your needs. On my new Wrico 12kw, I have a remote mounted radiator and a 16" electric fan. It only consumes 3.5 amps, but is a bit on the loud side when cranked up. So I had Dick Wright include an electronic motor speed control so when I'm in a campground, I can slow the fan down to silent run-both for sound and you don't need as much cooling when standing still. Good Luck, TomC |