Inaccuracies in the inverse heat conduction problem solution and their effect on the estimation of heat fluxes during quenching
Camila Gomez, Rens Nieuwenhuizen, C.W.M. van der Geld, J. G. M. Kuerten, M. Bsibsi, B.P.M. van Esch
Abstract
Solving the Inverse Heat Conduction Problem (IHCP) is a common approach to estimate the surface heat fluxes involved in transient, quenching experiments. The inverse problem presents several challenges, such as accounting for the non-uniqueness of its solution, for the effects of noise, or for other practical issues affecting the experimental input data, such as the thermal contact of the internal temperature sensors. In this paper, possible sources of inaccuracy in the IHCP solution and their effect on the estimated surface heat flux in experiments on quenching by water jet impingement are systematically investigated. A “virtual experiment” approach is followed to analyze the effect of a noise cancelling technique, the ambiguity in initial conditions and the quality of the thermocouple contact on the accuracy of the heat flux estimations. The results show that the invalid assumption of perfect thermal contact between thermocouple and test plate leads to overestimation of surface temperature in the initial stages of quenching. Based on these results, two measures are proposed to avoid misinterpretation of quenching heat flux estimations when solving the IHCP.