Alternative Calorimetry Based on the Photothermoelectric (PTE) Effect: Application to Magnetic Nanofluids

Abstract : Photothermoelectric (PTE) calorimetry was applied for the first time for thermal characterization of liquids. Both back and front detection configurations, together with the thermal-wave resonator cavity (TWRC) scanning procedure, have been used in order to measure the thermal diffusivity and thermal effusivity of a particular magnetic nanofluid: carrier liquid—transformer oil, surfactant—oleic acid, nanoparticles’ type—Fe3O4.The investigations were performed as a function of the nanoparticles’ concentration. Small increases of thermal diffusivity (from 9.06×10−8m2⋅s−1 up to 9.84×10−8m2⋅s−1) and thermal effusivity (from 450W⋅s1/2⋅m−2⋅K−1 up to 520W⋅s1/2⋅m−2⋅K−1) with increasing concentration of Fe3O4 nanoparticles (from 0 up to 0.623 mg Fe3O4/ml fluid) were observed. The comparison with the photopyroelectric (PPE) method shows that PTE and PPE give similar results but, for the moment, PPE is more accurate.