Overall Heat Transfer Coefficient Definition. 1u r 1h1eλ1h2. The overall heat transfer coefficient u is related to the total thermal resistance and depends on the geometry of the problem.
Purdue university researchers have shown that the. T1 in t2 out 1 t1 out. It is defined in combination with the area a eg.
The overall heat transfer coefficient is employed in calculating the rate of heat transfer from one fluid at an average bulk temperature t 1 through a solid surface to a second fluid at an average bulk temperature t 2 where t 1 t 2.
Thus area is included in the equation as it represents the area over which the transfer of heat takes place. For example heat transfer in a steam generator involves convection from the bulk of the reactor coolant to the steam generator inner tube surface conduction through the tube wall and convection boiling from the outer tube surface. Purdue university researchers have shown that the. Such a heat transfer coefficient is commonly called overall heat transfer coefficient.