Method to determine thermal stresses in thick-walled components; involves deriving internal wall temperature, mean wall temperature and thermal stress from series of measured metal temperature values

摘要

The method involves direct measurement of a series of metal temperatures, TM, on the metal surface of the component, and supplying the data to a computer circuit in which the internal wall temperature, the mean wall temperature and the thermal stress are computed according to a given set of mathematical relationships. The internal wall temperature, Ti, is calculated from the equation, Ti = EPSILON mu =0n (a mu TM(tk - (n - mu ) DELTA T), the mean wall temperature, Tm, is calculated from the equation, Tm = EPSILON mu =0n (b mu TM(tk - (n - mu ) DELTA T) and the thermal stress, sigma , is calculated from the equation, sigma = C(Tm-Ti), where tk is the actual time, DELTA T is the adjusted down time, n is a parameter corresponding to the selected development number, mu is an integer between 0 and n, a mu and b mu are amplification factors, and C is the material constant. An Independent claim is also included for a circuit for implementing the method.