3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
(OP)
I'm trying to determine what the temperature rise will be of a 1 cu. ft. of air, moving at 2640 CFM, when exposed to a flame emitting 3000 BTU's. The volume of air is introduced at standard pressure and at 100°F.
The situation is this:
I have an open flame that was calculated to have an output of 3000 BTU's. Approximately 100 feet away from this flame, I have some material that will fail at a given temperature (haven't been told what that temp is yet). This is an outdoor environment and I don't really know what the air movement is so for now I'm assumption that it's 2640 CFM (30 mph). I'm thinking this isn't much different than a heating system for a house. The heating systems give off X Btu's which should raise the temperature X °F, from a given temperature.
Can someone help me figure this out?
The situation is this:
I have an open flame that was calculated to have an output of 3000 BTU's. Approximately 100 feet away from this flame, I have some material that will fail at a given temperature (haven't been told what that temp is yet). This is an outdoor environment and I don't really know what the air movement is so for now I'm assumption that it's 2640 CFM (30 mph). I'm thinking this isn't much different than a heating system for a house. The heating systems give off X Btu's which should raise the temperature X °F, from a given temperature.
Can someone help me figure this out?
Regards,
Dan Marr
www.advantagefireprotection.com
"Real world Knowledge isn't dropped from a parachute in the sky but rather acquired in tiny increments from a variety of sources including panic and curiosity."





RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
Chinese prisoner wins Nobel Peace Prize
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
At any rate the effect of a smallish flame, 100 feet away from an unknown quantity of an unknown material outside on a windy day will be approximately nothing.
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
23ms*3000 BTU/hr = 20.2 J
Specific heat of air = 1005 J/kg-K
density of air at 25C = 1.18 kg/m2
A bit more algebra results in 0.6°C temperature assuming blah, blah, and blah...
This is not at all surprising, is it? a 3000 BTU/hr burner is like a stove top set to medium flame. You can barely perceive the infrared thrown off by large gas patio heaters from more than about 10 ft away.
I've completely ignored the obvious fact that the heated air is more buoyant and more energetic, so it's highly unlikely that something that remote would see even 1/10 of the temperature rise calculated.
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
Chinese prisoner wins Nobel Peace Prize
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
It's simple. Add 3000 Btu/hr to 2640 cfm:
Q = 1.08 * cfm * dT, Q is in Btu/hr and dT is in °F
Q = 1.08 * cfm * (T2 – T1)
T2 = (Q / (1.08 * cfm)) + T1
T2 = (3000 / (1.08 * 2640)) + 100
T2 = 101°F
You have a 1°F (or a 0.6°C) rise.
RE: 3000 BTU's will raise 2640 CFM of air, from 100¦F to What, in 1 Min?
You're right, I did it a roundabout...
TTFN
FAQ731-376: Eng-Tips.com Forum Policies
Chinese prisoner wins Nobel Peace Prize