Calculating tube growth in furnace

[Patassa]

We're working on a client package to install new tube skin TIs in one of their vertical circular furnaces. One of the requirements is to specify the direction of tube growth and the growth dimensions where the TIs will be located on the tubes.

Is there any guidance or examples of this that I can look at? It seems like this would have to be done on software rather than by hand, but if it can be done by hand could someone give me some guidance? I'm not sure how to correctly solve this and give an answer that would pass scrutiny by the client. It seems more complicated than a basic thermal expansion calculation of a straight piece of pipe, obviously.

 

[RoboCop16]

Hmmm, you don't mention why it is required to know the tube growth to install the TI's. Without that being known, it is difficult to understand what is required in terms of calculation and calculation accuracy.

Unless you have existing calculations for the same or similar furnaces - or an existing software designed to simulate mechanical behaviour of the furnace - I don't think there is any short-cut to studying the design of the furnace to understand how it will expand under temperature. I.e. you must understand how it is supported, know the materials and temperatures and design a mathematical model to replicate the thermal growth. Some engineering judgement may be needed to arrive at a simple model, commensurate with the, probably moderate, accuracy required.

I understand this to be an existing furnace in which case maybe it is an alternative to simply do measurements in both the cold and hot condition?

 

[Patassa]

Hi Terp

It's required to make sure that the expansion in the tubes doesn't exceed the expansion loop length in the leads to the TIs. Getting the hot conditions and waiting for the cold conditions is not an option.