O.K. couple things.
What is an accetable temp variance? 104 is a nice target but I doubt you are going to achieve that along the whole length of tube.
221 amp @ 240 volts ? is this constant or can this be varied? Am I to assume 100% heat creation or is there an efficiency on those?
Right now I am at 53kW.
How long is the 17 dia tube?
What is the tube made of?
what is the surface area of the coils?
Wall thickness of the tube?
As a rough guide line I would approach it this way.
Find out what the steady state heat load the tube can handle so that the outer temp is 104 degrees. (pretend there isn't anything inside, purely theorectical)
Lets say that is 5kW (total guess, purely for disucssion)
Then use the internal air temp calculated and that heat load value determine how much heat in Kilowatts you need to dissipate, 53kW - 5Kw = 48kW @ 120 degsF <-- pure example again.
Then use the thermodynamic equation to come up with how much air flow in CFM needs to go through assuming you have a heat gain of [CFM(120 degsF - Ambient)] = 48kW <-- not a formula just for reference.
StrykerTECH Engineering Staff