Metal surface temperature (heat trough a wall)
Metal surface temperature (heat trough a wall)
(OP)
Hi All,
I have a question here, a pipe with inside medium temperature known and outside surrounded by air, pipe dimension also know, eg thickness, diameter, material thermal conductivity. How to find out the metal surface temperature on the outside of the pipe? I would assume the metal temperature on the inside of the pipe is same as the medium?
Could be a very simple question for you experts. or is there to many unknown?
I have a question here, a pipe with inside medium temperature known and outside surrounded by air, pipe dimension also know, eg thickness, diameter, material thermal conductivity. How to find out the metal surface temperature on the outside of the pipe? I would assume the metal temperature on the inside of the pipe is same as the medium?
Could be a very simple question for you experts. or is there to many unknown?





RE: Metal surface temperature (heat trough a wall)
Depends on the thermal conductivity and thickness of the pipe.
As for the surface temperature, by using the continuity relationship, you can equate the conducted heat flow to the convected heat flow from the surface to the air. My last post in thread391-378531: Heat Conduction through a Wall has a similar situation, but with both inner and outer surface temps unknown.
TTFN

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RE: Metal surface temperature (heat trough a wall)
2. What is the fluid flow rate, pipe ID, and pipe diameter? To calculate anything useful, you need to estimate/know/specify/guess a fluid velocity and the fluid properties to get the actual assumed fluid film coefficient.
3> horizontal or vertical pipe?
read the previous thread on concrete wall temperature. Your problem is the same. But completely different. 8<)
RE: Metal surface temperature (heat trough a wall)
2 let assume 610 diameter, 2mm wall. flow rate unknown, can we assume the inside can keep maintain it hotness regardless of ambient temperature.
3 dose orientation matters?
Q = thermal conductivity * area * delta temperature / thickness
There are two unknown in this equation, Q and dT. What I want to find out is dT.
how to find the heat flow?
Thank you
RE: Metal surface temperature (heat trough a wall)
Nevertheless, 2-mm thickness of most metals like cast iron or carbon steel will only result in about 0.03C drop, so the assumption that the wall temperature is not unreasonable. However, the heat flow per meter of length is more than 500W, so the temperature of the fluid will drop as it travels down the pipe, unless the thermal mass flow is sufficiently high enough to mitigate that.
TTFN

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RE: Metal surface temperature (heat trough a wall)
RE: Metal surface temperature (heat trough a wall)
Does orientation of the pipe matter?
only if you want to get the right answer? How long a pipe running in what direction beginning at what temperature fluid inside the pipe is ESSENTIAL in figuring out how much heat is lost into a room filled with stagnant air when all of the heat energy is going to be lost by natural circulation!
Are you going to assume the room temperature air is going to stay the same? If so, what is the hottest expected room temperature? Or is the problem the maximum heat lost, and you are worried about the lowest expected room temperature?
With no other information, the answer is, obviously, 6.37 Or 1361.2 8<)
RE: Metal surface temperature (heat trough a wall)
RE: Metal surface temperature (heat trough a wall)
RE: Metal surface temperature (heat trough a wall)
TTFN

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Need help writing a question or understanding a reply? forum1529: Translation Assistance for Engineers
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