Selected thermal parameters of bioethanol samples

This article deals with thermal properties of selected bioethanol samples. Ethanol (CH3CH2OH) is a clear liquid. Also known as ethyl alcohol, grain alcohol, and EtOH, the molecules in this fuel contain a hydroxyl group (OH -) bonded to a carbon atom. Ethanol is made of the same chemical compound regardless of whether it is produced from starch and sugar-based feedstocks, such as corn grain, sugar cane etc. For thermal parameters measurements was used hot wire method. The experiment is based on measuring of the temperature rise vs. time evaluation of an electrically heated wire embedded in the tested material. The thermal conductivity is derived from the resulting change in temperature over a known time interval. For two samples of bioethanol were determined basic thermophysical parameters - thermal conductivity and thermal diffusivity. For each bioethanol sample were made two series of measurements. In the first series were measured thermal conductivity and thermal diffusivity at constant room temperature 20 °C. Every thermophysical parameter was measured 10 times for each sample. The results were statistically processed. In the second series of measurements were measured relations of thermal conductivity and thermal diffusivity to the temperature in temperature range (20 - 29) °C. From results was evident that all measured dependencies are nonlinear. For both thermophysical parameters were obtained polynomial functions described by the polynomial coefficients. Type of function was selected according to statistical evaluation based on the coefficient of determination for every thermophysical parameter graphical dependency. All obtained results are presented on figures 1 and 2 and in the tables 1, 2. The results of thermophysical parameters measurements of bioethanol were compared with the values λ and a presented in the literature.