Measurement methods based on the hot plate did not consider the exchange coefficients around the device. These measurements were based on analytical solutions of the unidirectional (1D) heat conduction equation. This paper describes an experimental method to simultaneously estimate the thermal conductivity and thermal diffusivity of materials, considering the exchange coefficient around the device. This paper describes an experimental method for simultaneously estimating the thermal conductivity and thermal diffusivity of materials, considering the exchange coefficient around the device. This method is based on the measurement of the temperature at the center of a heating element inserted between two samples, with the unheated surface of the samples being kept constant. First, a three-dimensional (3D) heat transfer model was established. This model was solved using the finite volume method (FVM) and implemented in MATLAB®. A simulation of the 3D model in COMSOL Multiphysics was performed to simulate the temperature field. Estimates made from these simulations show that the estimation error can be greater than 10% for very short times. This 3D model was then used to perform a sensitivity analysis on the different thermophysical parameters and the convection coefficient. The Levenberg-Marquardt algorithm was used to calculate the estimates. An experimental study was performed on several material samples, leading to an estimation of their thermal properties. In addition, a comparative study based on the asymmetric hot plate (AHP) method is performed, and the results obtained showed a relative error of less than 5%. Therefore, it can be concluded that the proposed model is validated to provide reliable thermophysical properties of materials.

In this study, a numerical model of the asymmetric hot plate method was developed to determine the thermal properties of materials. The proposed model considers the convective heat loss around the device. First, a numerical calculation code is developed to determine the temperature evolution at the measurement points. This calculation code is then used to perform a reduced sensitivity study on various parameters. The Levenberg-Marquardt algorithm was used to identify the thermal properties of different materials from the thermogram. The impacts of the convection coefficient h and insulation thickness on the calculation of the estimates were studied. Finally, an experimental study was conducted using several materials. The thermal properties were compared with experimental results obtained using other measurement methods. A satisfactory agreement was obtained.

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