Temperature drop along steam pipes
Temperature drop along steam pipes
(OP)
Hello,
I have searched without much luck. I am curious as to what sort of rough numbers you would be looking at in terms of a temperature drop of the pipe surface along a pipe run. Say at one location the pipe surface temperature was measured at roughly 315 deg F, it has steam inside at roughly 100 psig and flowing constantly at maybe 100 ft/s, and the pipe is 1" nominal size Schedule 40 rusty steel pipe. Also this would be inside with a fairly warm ambient temperature of 85 deg F or so.
100 feet down the pipe run, what is a reasonable temperature to assume for the pipe surface? I am guessing that it will only drop by 5 deg F or less per 100 ft, given the warm ambient temperature.
Thanks.
I have searched without much luck. I am curious as to what sort of rough numbers you would be looking at in terms of a temperature drop of the pipe surface along a pipe run. Say at one location the pipe surface temperature was measured at roughly 315 deg F, it has steam inside at roughly 100 psig and flowing constantly at maybe 100 ft/s, and the pipe is 1" nominal size Schedule 40 rusty steel pipe. Also this would be inside with a fairly warm ambient temperature of 85 deg F or so.
100 feet down the pipe run, what is a reasonable temperature to assume for the pipe surface? I am guessing that it will only drop by 5 deg F or less per 100 ft, given the warm ambient temperature.
Thanks.





RE: Temperature drop along steam pipes
RE: Temperature drop along steam pipes
It'll probably drop about the amount you say, but not because of the warm ambient; it's because the steam is exposed to that section of pipe for only 1 second.
TTFN
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RE: Temperature drop along steam pipes
RE: Temperature drop along steam pipes
RE: Temperature drop along steam pipes
TTFN
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RE: Temperature drop along steam pipes
RE: Temperature drop along steam pipes
So, Compositepro, I can just calculate the pressure drop and then that gives me the temperature drop? I am assuming this is using the ideal gas law, but I thought steam was not an ideal gas? But assuming it is we have delta P = delta T, is that correct?
RE: Temperature drop along steam pipes
RE: Temperature drop along steam pipes
I know I have a tables of heat loss for steam lines someplace, but it's awkward to look for just now. Try Spirax-Sarco's literature and/or website.
RE: Temperature drop along steam pipes
At 315 F the steam is saturated at 83.5 psia.
If there is a 5 psi drop in the line, the end pressure is 78.5 and the saturation temperature is 311 F.
If there is a 10 psi drop in the line, the end pressure is 73.5 and the saturation temperature is 306 F.
You can get this from a steam table. You need to calculate the pressure drop through the line to get the real answer.
Regards,
Speco
RE: Temperature drop along steam pipes