Comprehensive Assessment on the Use of Boron Nitride-Based Nanofluids Comprising Eutectic Mixtures of Diphenyl Ether and Menthol for Enhanced Thermal Media
Pyarimohan Dehury, Upasana Mahanta, Tamal Banerjee
Abstract
The current work explores deep eutectic solvents (DESs) as heat transfer fluids (HTFs) primarily for generating concentrated solar power. The eutectic composition of the DES comprising diphenyl ether and dl-menthol as the hydrogen bond acceptor and hydrogen bond donor was initially computed through the quantum chemical-based COSMO-SAC model. To improve upon the thermal performance and reduce the interfacial resistance, DESs were modified by dispersing hexagonal boron nitride nanoparticles with weight percent ranging from 0.02 to 0.10. Thermophysical properties, namely, density, viscosity, thermal conductivity, and heat capacity, of the HTFs were then measured as a function of temperature. Further, based on these four parameters, the Mouromtseff number (Mo) was calculated to rank the nanoparticle-dispersed DESs. The nanofluid consisting of DES-1 with 0.02 wt % of nanoparticles gave the highest Mo value, and hence, it was further considered for the experimental forced convection study and process simulation using an Aspen Plus simulator. From the forced convection experiment temperature profiles, the heat transfer coefficient and Nusselt number (Nu) were evaluated and compared for nanofluids with the corresponding base fluid. The flow behavior of the thermal fluid along the characteristic length of the test section was investigated for both the laminar and turbulent regimes. The effectiveness of the HTF in terms of steam generation capacity was predicted, and it was observed that the nanofluid with 0.02 wt % was able to successfully convert 100% of the input water (15 kg/h) into superheated steam at the temperature of 494.15 K.