Model for Cuboid Shape Samples and its Analysis Used for Measurements of Thermophysical Properties of Sandstone

Abstract

A new model for the sample of square cross section with cuboid geometry including the effect of heat loss from the surface of the sample was tested using the theory of sensitivity coefficients. Theoretical calculation of model uncertainty and derived analytical formulas are presented. Results of the uncertainty analysis set out the range of experimental conditions under which the model is valid and the uncertainty of estimated parameters is low. Propagation of error for non-stochastic dynamic measurements based on the sensitivity coefficients shows limitations related to a range of model validity. The analysis improves the accuracy of measurements. The model was used for data evaluation of thermophysical parameters measured on the sandstone from the locality Pravčická brána. Evaluation procedure was tested on experimental data measured under different experimental conditions. In conclusion, the discussion of the experiment optimization is presented.

The Combined Relative Uncertainty of Measurement Results by Prototype Semi-Automated Calorimetric Chamber

“…The paper illustrates the uncertainty of the result of the measurement of the specific thermal capacity of the selected thermal insulation concrete. Theoretically, it is a comparison of the calorimetric equations of the investigated sample and the comparative etalon (16), including the evaluation of the combined relative uncertainty of the measurement result (17) to (20). Calculation of the mean value of the specific thermal capacity of the investigated sample is performed by means of a tabulated value of the specific thermal capacity of the comparative etalon, by weighing of both samples and by indirect measurements of the temperature differences between the opposite walls of the investigated sample and of the comparative etalon during the stationary heat flow.…”

“…At present, non-stationary pulse transient methods are used and developed. They are based in principle on the fact that the planar source of heat generates a thermal impulse and the thermal response to this thermal impulse is recorded by a thermocouple placed separately from the heat source, it is analyzed and adequately interpreted [17]. The commercial measuring instrument Isomet 2114 uses the same principle, i.e.…”

Thermophysical Parameters of Carbonate Rock estimated by Slab Model Developed for Pulse Transient Technique

“…Also in the experiment technically the heat pulse used is not an ideal Dirac function but a heat pulse of limited duration. [15], [16], [17], [18], [19].…”

“…2. The slab model for infinitely large specimens accounting the heat source heat capacity as well as the heat transfer coefficient in between the heat source and specimen body is drowned with the experimental parameters and geometry of arrangement [15], [16], [17], [18], [19].…”

“…The slab model used in this paper is accounting for these two effects by using the calculation and analysis of the sensitivity coefficients that are serving for the calculation of the uncertainties of free parameters [13], [14], [15] see Fig. 5.…”