A NONLINEAR INDIRECT MEASUREMENT PROBLEM FOR A MULTITHERMOCOUPLE PROBE IMMERSED IN A LIQUID

Abstract

The problem described herein concerns the processing of the time-dependent, internal temperatures within a multithermocouple probe. These are used to compute the temperature of the surrounding fluid, as part of an inverse heat conduction problem (IHCP). The novel achievement in this work is that the exchange coefficients do not have to be supplied a priori, but instead are an additional solution output. Consequently the IHCP is nonlinear and requires significant stabilization. Four methods are applied successively, until a satisfactory solution is found: the parameterization of spatial variations in fluid temperatures and exchange coefficients; a functional specification method (using future time data) to address the noncausal nature of the solution; a lower bound on the exchange coefficient; and a maximum number of iterations at each time step (in accordance with the discrepancy principle).