Accounting for Sensor Errors in Estimation of Surface Heat Flux by an Inverse Method

Abstract

Thermocouples or other measuring devices are often embedded into a solid to provide data for an inverse calculation. It is well-documented that such installations will result in erroneous (biased) sensor readings, unless the thermal properties of the measurement wires and surrounding insulation can be carefully matched to those of the parent domain. Since this rarely can be done, or doing so is prohibitively expensive, an alternative is to account for the sensor dynamics with an appropriate model. In this paper we simulate a thermocouple embedded in a sand mold near the interface of a solidifying aluminum casting. The effect of sensor errors is accounted for by generating correction kernels from a detailed model of the embedded thermocouple. The corrected sensor readings are used in the inverse heat conduction solution. The magnitude of the effect is shown by comparing surface heat fluxes computed with measured temperatures to the heat fluxes computed with corrected temperatures.