Estimation of Temperature-Dependent Thermophysical Properties of Noncharring Ablators

摘要

The Levenberg-Marquardt method is used for simultaneously estimating the temperature-dependent thermal conductivity and specific heat of noncharring ablators with moving boundary over a wide temperature range up to 5000 K. It is assumed that no prior information is available on the functional forms of the unknown thermal conductivity and specific heat in the present study. A special feature about the proposed method is that the net surface heat flux and ablative mass flux are unknown a priori and must be determined at each time step. The measured temperatures are simulated numerically by the Charring Material Ablation code that accounts for unsteady ablation. Particular emphasis is placed on the sensitivity analysis, in which the role of sensor location and number of sensors in the estimation of thermal properties can be best appreciated. Considering the nonlinear nature of the proposed inverse problem, it is shown via simulated experiment that unknown parameters can be achieved with reasonable accuracy using this method despite the correlation of the involving parameters and the existing noises in the measurement data.