Heat Transfer Through a Tube
Heat Transfer Through a Tube
(OP)
I am currently using nitrogen gas as a coolant. The tube length from dewar to coolant nozzle is appox 20ft. It's coming out of the coolant nozzle at 72°F. I need to cool the gas to ~40-50°F. I was thinking of running the tube through a tub of ice to cool the Nitrogen as a simple solution. I can disconnect the tube from the dewar and add extra length as needed to coil it in the tub. I'm trying to calculate how much of the tube needs to be in the ice.
I've been trying to use Q=2*pi*L*k(Ti-To)/(ln(ro/ri))
where:
Tube - Polyurethane - k=0.02 (W/m*K)
L - unknown
Ti=72°F
To=32°F
ro=0.1875in
ri=0.126in
I've had no luck and seem to be going in circles. What am I missing? Any help is appreciated.
Thanks,
DJ
I've been trying to use Q=2*pi*L*k(Ti-To)/(ln(ro/ri))
where:
Tube - Polyurethane - k=0.02 (W/m*K)
L - unknown
Ti=72°F
To=32°F
ro=0.1875in
ri=0.126in
I've had no luck and seem to be going in circles. What am I missing? Any help is appreciated.
Thanks,
DJ





RE: Heat Transfer Through a Tube
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RE: Heat Transfer Through a Tube
RE: Heat Transfer Through a Tube
So you're looking for a refrigerator-type regulated cooler whose control is based NOT on the water bath temperature but on the outlet of the N2 coming out of the cooler (if a irregular N2 flow) or on the water bath (if a constant N2 flow).
Just cooling the N2 is fairly simple - but we need to know the size of your N2 lione and the mass flow of the N2 - you didn't mention either! Cooling a small N2 line is easy. Over-cooling is even easier.
A big N2 line? Cool the N2 tank with that regulated cooler with lines wrapped around the N2 tank. Then just insulate the N2 line against heat flow.
RE: Heat Transfer Through a Tube
he has a slew of observed points WITH REFRIGERANT gasses in his cool-ing HX coils
I just bought 3 , 1 for w:w radiant; and two for DX r22 system, shell around coils.
Mention "JP" and he may have a moment to square up your calcs- est's... (not to buy, just he is friendly)
he has surface sq ft and all from small to quite large.
2)
Any hope of non-refrigerant cooling of your gas with an oversized Earth-Coupled Loop (ECL) like we use in GeoThermal- Heat Pumps ground loops?
Ditch or pond or horizontal borehole Earth-Coupled Heat Exchange for the process in ? do you have 45f soil?
RE: Heat Transfer Through a Tube