Eventos Anais de eventos
COBEM 2021
26th International Congress of Mechanical Engineering
THERMOPHYSICAL PROPERTIES CHARACTERIZATION OF MoS2/H2O-EG FOR HEAT TRANSFER APPLICATIONS
Submission Author:
Felipe Silva dos Santos , MG , Brazil
Co-Authors:
Felipe Silva dos Santos, Edwin Martin Cardenas Contreras, ENIO PEDONE BANDARRA FILHO
Presenter: Felipe Silva dos Santos
doi://10.26678/ABCM.COBEM2021.COB2021-0387
Abstract
Nanofluids are heat transfer fluids with potential to replace traditional fluids (water, ethylene glycol, oil, etc) and largely used for thermal energy transport applications. As a two-dimensional material, molybdenum disulfide (MoS2) has drawn wide attention due to properties and application prospects. In this work were evaluated the stability and thermophysical properties for different low concentrations (0.02-0.1 wt.%) of molybdenum disulfide (MoS2) to a mixture of water-ethylene glycol H2O-EG (50:50 in vol.%) in the presence of stabilizing agent, with focus on the heat transfer application. Two-step preparation method was used to produce the samples, where solid particles are pre-synthesized for hydrothermal method, separated, dried and then dispersed in the base liquid of interest. For a complete dispersion and reduction of nanoparticles cluster size, ultrasonic stirring and magnetic vibration were available. The addition of surfactant can improve the stability of the suspensions due the improvement of electrostatic stability, however their use can modify the nanofluids thermophysical properties, ie. viscosity, specific mass and thermal conductivity. The viscosity and density of nanofluids were investigated at 20-50 °C and the thermal conductivity was measured using the transient hot-bridge method at 20-50 °C. The structural characterization of nanofluid samples was studied by obtaining the optical absorption spectra using the UV-Vis spectroscopy, at the same wavelength for different concentration of nanofluid, commonly utilized to determine the stability of the nanofluids by a linear relationship between the absorbance and the concentration which follow the Beer-Lambert Law. UV-Vis absorbance of a nanofluids samples is a direct relationship with weight concentration. The morphological structure was analysed using SEM to determine the agglomeration of particles by showing the size, shape, and distribution within the nanofluid. From the experimental results obtained it was possible to conclude that due the long-term stability and high thermal conductivity identify the MoS2/H2O-EG as a favourable additive in thermal energy engineering.
Keywords
Molybdenum disulfide, Heat transfer, stability, thermal conductivity, UV-Vis spectroscopy
