با سلام..
https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&cad=rja&uact=8&ved=0ahUKEwiUr_GcqcLKAhUH2xoKHSCxAXEQFggcMAA&url=http%3A%2F%2Fwww.homepages.ucl.ac.uk%2F~ucecesf%2Ftmp%2Fheatandpipes.pdf&usg=AFQjCNF07RiNr7BECx8ZYJ-o26tEbEJraA&bvm=bv.112454388,d.ZWU