PREDICTION OF FLUID TEMPERATURES FROM MEASUREMENTS OF OUTSIDE WALL TEMPERATURES IN PIPES

The monitoring of the fatigue induced by thermal transients in thick-w alled structures becomes more and more currently performed, mainly on equipment the failure of which could present severe implications on th e environment. The easiest way of performing this monitoring is by use of Green's functions in a convolution integral of the measured fluid temperatures to assess the stresses at the points of interest. Numerou s cases, however, exist where the fluid temperatures are not available and only an outside wall temperature measurement is feasible. This pa per describes the development and the industrial application of the so -called ''inverse'' transfer functions to predict the evolution of the fluid temperature from measurements of the metal temperature either a t the outside or in the wall of the considered equipment. Some applica tions are shown for the particular case of the thermal stratification in piping systems.