Check out the engineer's toolbox. They have the info.
Concentric Tube Heat Exchanger
The three heat transfer operations that need to be described: - Convective heat transfer from fluid to the inner wall of the tube, - Conductive heat transfer through the tube wall, and - Convective heat transfer from the outer tube wall to the outside fluid. This would be of great help: web.mit.edu/16.unified/www/FALL/t...
