5 replies to this topic

[SPF]

This is probably a bit back to basics but having not carried out any heat transfer work in a while I find myself a tiny bit forgetful!

 

We are trying to find out how bit the temperature rise is in a piece of pipe with a liquid flowing through it. This pipe is insulated but between the insulation and the pipe are two smaller heating lines acting as a coil to heat this inner pipe.

 

I am assuming that I need the following;

 

Pressure of steam - to caclulate temperature and assume that temperature of steam doesn't change throughout the coil.

 

Flow of liquid in inner pipe as well as physical properties (Cp, temperature).

 

Physical properties of pipe (heat transfer coefficient).

 

I am guessing that I can assume for ease that the insulation keeps all the heat coming from the steam within the area exposed to the inner pipe.

 

From here on, I am a bit forgetful!

 

Can anyone please guide me on what method I would follow to calculate the temperature coming out of a section of this pipe?

 

Thanks in advance.

[Bobby Strain]

You should be able to find what you need with a GOOGLE search.

 

Bobby

[latexman]

Look around in some steam trap websites.

[PingPong]

Tracing is normally intended to compensate for heat loss from the process pipe through the insulation to the environment. Assuming that that heat loss is zero makes therefor little sense.

 

Unless there is a heat transfer compound (cement) used to attach the tracers to the process pipe it is not possible to calculate the heat gain of the process fluid, because it is impossible to know what the contact area between the tracers and the pipe is.

 

If spacer blocks were installed between the tracers and the process pipe, then heat transfer between tracer and piping is via natural convection via air inside the insulation, which is very low, and radiation, which depends on the emissivity of the metal surfaces of tracer and process pipe.

Edited by PingPong, 09 October 2014 - 01:26 PM.

[Padmakar Katre]

This is probably a bit back to basics but having not carried out any heat transfer work in a while I find myself a tiny bit forgetful!

 

We are trying to find out how bit the temperature rise is in a piece of pipe with a liquid flowing through it. This pipe is insulated but between the insulation and the pipe are two smaller heating lines acting as a coil to heat this inner pipe.

 

I am assuming that I need the following;

 

Pressure of steam - to caclulate temperature and assume that temperature of steam doesn't change throughout the coil.

 

Flow of liquid in inner pipe as well as physical properties (Cp, temperature).

 

Physical properties of pipe (heat transfer coefficient).

 

I am guessing that I can assume for ease that the insulation keeps all the heat coming from the steam within the area exposed to the inner pipe.

 

From here on, I am a bit forgetful!

 

Can anyone please guide me on what method I would follow to calculate the temperature coming out of a section of this pipe?

 

Thanks in advance.

Hi,

Search with keywords like Steam Tracing in the forums you will find the useful stuff. If I recall correctly, few years back there was on spreadsheet and theory sheet uploaded on Cheresources website.

[SPF]

Thanks for some of the helpful comments above.