Heat transfer at altitude
Heat transfer at altitude
(OP)
Without going into to much detail, I am doing some ground work on how to heat the surface area of an elevated platform. I have scoured all my heat transfer texts (not many as a mech.production engineer) and can only find equations relating to pipelines,fluid flow etc... and not a static flat structure.
Can anyone suggest a suitable text or correct formulae. Obviously there are many factors which will come into play later (wind speed,platform material and construction etc..) but at this stage I am more interested in getting the theory right.
All help greatly appreciated.
Can anyone suggest a suitable text or correct formulae. Obviously there are many factors which will come into play later (wind speed,platform material and construction etc..) but at this stage I am more interested in getting the theory right.
All help greatly appreciated.





RE: Heat transfer at altitude
http://www.egr.msu.edu/~somerton/Nusselt/ii/ii_a/ii_a_1.html
Follow this link and you will get plenty of Nusselt expressions for various conditions.
Regards,
RE: Heat transfer at altitude
Unfortunateley , the link given just leads to dead pages. I understand you thinking this is a simple problem but maybe I should expand slightly.
The platform I am looking at is a large surface area and will be exposed to extremeley low ambient temperatures and high (but irregular) wind chill factors. Therefore the heat losses are going to be massive, fluctuating and unevenly distributed. I don't want to use basic theory and then find that I should have used more sophisticated formulae. I was hoping that there may be some theory to cover this type of arrangement. I shall battle on bravely !
Regards.
RE: Heat transfer at altitude
RE: Heat transfer at altitude
Perhaps you will need to "solve" your large surface with a Finite Element Analysis. This is especially so if you are interested to know the thermally induced stresses in your structure.
But, you should understand that the FEA tools use the same basic correlations of convective h.t. as QUARK has pointed you to. There is nothing inherently primitive or "unsophisticated" about such h.t. correlations. You can calculate local convective coefficients, or an averaged coefficient for a surface. Many effects may be arithmetically summed.
RE: Heat transfer at altitude
Did you try ASHRAE 2001 (or earlier) Fundamentals? Most college libraries will have it (and Steinberg's books) if they have an engineering school.
Bruce
RE: Heat transfer at altitude
Project has now taken a significant step forward.
Thanks again !