THE INFLUENCE OF NANOPARTICLES Al2O3 ON ISOPROPYL ALCOHOL HEAT CAPACITY

New experimental data for the heat capacity on the saturation line for the pure isopropyl alcohol and nanofluids (solutions of the isopropyl alcohol and nanoparticles Al2O3) have been reported in the paper. We also present the description of the experimental setup that realizes method of direct heating in adiabatic calorimeter. The calorimeter has been used for experimental investigation of the heat capacity for pure isopropyl alcohol as well as nanofluids (solutions of the isopropyl alcohol and nanoparticles Al2O3) in temperature range from 190 to 324 К at weight fractions of nanoparticles 0,515%, 1,027%, 1,972%. The procedure of fitting for the obtained experimental data is reported. The analysis shows that mean uncertainty of measured data does not exceed 0,75%. Obtained data indicate that admixtures of nanoparticles Al2O3 lead to decreasing the heat capacity of the liquid phase of isopropyl alcohol. In addition, an influence of the nanoparticles Al2O3 on heat capacity increases at increasing the absolute temperature from 0,5% at melting point to 6% at temperature equal to 330 K. We have also found that models proposed by Pak-Cho and Xuan-Roezel predict higher values of the heat capacity for the nanofluids. The deviations of calculated values from experimental data increase with increasing the temperature. It should be noted that Xuan-Roezel model give more correct temperature dependence for the nanofluids isopropyl alcohol/nanoparticles Al2O3. Based on experimental data obtained we proposed new “3-phase” prediction model for the heat capacity of the nanofluids. The proposed model takes into account excess mole heat capacity. This value can be determined as heat capacity of the surface layer which is formed on the surface of the nanoparticle due to sorption. Тhe surface layer can be assumed as molecules of the base liquid. We would emphasize that value of excess heat capacity of the nanofluids correlated with changing of hydrodynamic radius of the nanoparticles.