Investigation on the Electrical and Rheological Properties of AlN-Based Synthetic Ester Nanofluids

The present study deals with the characterization of electrical and rheological behaviour of the Synthetic ester fluid incorporated with various concentration of Aluminium nitride (AlN) nanoparticles. Zeta potential measurement has shown an excellent stability of the ester fluid mixed with the nanoparticle. Corona inception voltage (CIV) measured using ultra-high frequency (UHF) technique and the results confirmed higher discharge resistance for nanofluid dispersed with 0.005% of AlN. Phase resolved partial discharge (PRPD) analysis with higher harmonic voltages has shown increase in pulse magnitude and number of discharges. Dielectric constant and tan 8 measurements have revealed a slight marginal increase in its value with the inclusion of filler. Streaming current magnitude was found to increase with the disc rotational speed, concentration of nanoparticle and ambient temperature. Fluorescence spectroscopy analysis has shown increase in fluorophores intensity with filler dispersion in the ester fluid. Rheological properties of fluids mixed with nanoparticles are inspected with cone plane geometry configuration. Synthetic ester and its nanofluid exhibited Newtonian behavior of flow pattern and are independent of the applied shear rate. An exponential decay of viscosity of nanofluids was observed with temperature and it follows an Arrhenius law. The calculated activation energy has increased with the incorporation of filler concentrations. The complex modulus of AlN nanofluids was observed alongside exhibiting the viscous behavior where the loss modulus G '' is much larger than the storage modulus G', with the applied frequency.

Automated summary

This study investigates the electrical and rheological behavior of synthetic ester fluid incorporated with different concentrations of aluminum nitride (AlN) nanoparticles. Results showed that the addition of AlN nanoparticles increases the discharge resistance and pulse magnitude, as well as the number of discharges. The dielectric constant and tan 8 values show a slight increase with filler inclusion. Streaming current magnitude increases with nanoparticle concentration. Fluorescence spectroscopy analysis indicates an increase in fluorophores intensity with filler dispersion. The rheological properties of nanofluids exhibit Newtonian flow pattern and the viscosity decreases exponentially with temperature following the Arrhenius law. The complex modulus of AlN nanofluids shows viscous behavior, with the loss modulus G'' much larger than the storage modulus G', as the frequency increases.