Parameter estimation procedure of model for pulse transient technique with heat loss effect verified on porous stone material

V. Boháč1, P. Dieška2 and Ľ. Kubičár1

1Instititue of Physics, Slovak Academy of Sciences, Slovakia

Keywords: pulse transient, parameter estimation, porous stone material
property: thermal conductivity, thermal diffusivity, specific heat, heat transfer coefficient
material: porous stone

Methodology of testing and parameter estimation for recently developed models for pulse transient technique has been performed. The sensitivity coefficients theory was used to analyze the aspects of measurement regime. The results of uncertainty analysis of free and constant parameters in models show effective time intervals available for the parameter estimation by fitting procedure as well as the set of the experimental parameters and specimen geometry for the measurement. The effects of heat loss from the sample surface as well as heat capacity of the heat source were implemented into a model. The effect of heat losses from the sample surface was solved via heat transfer coefficient in between the sample free surface and surrounding atmosphere. Models and subject of knowledge obtained from parameters estimation procedures were applied to data measurement on sandstone at different temperatures ranging from -20 up to 70 °C. Heat loss effect was tested at the measurements performed under the vacuum and air also. As the sensitivity coefficient of heat transfer parameter depends on time when it starts to take place, the new model was tested in measurements for different duration of the heat pulse also. In this way there were verified the geometry ranges and time intervals previously found by analysis, in connection with the influence of the disturbing effects that are take place during the measurement. Measurements of thermophysical parameters were done for dried sandstone material. It was found that during a measurement under vacuum conditions the material has undergo further drying process as the thermophysical parameters were lowered after loading back the atmosphere into a pores of the sample in measurement chamber RTB1.02. The described methodology promoted the quality of the measurement and helps to suppress the measurement uncertainty.

     Official Sponsors

uni Anter_logo Tziolas_logo_ linseis netzsch