Molecular dynamics study on the adsorption synergy of MWCNTs/MoS2 nanofluids and its influence of internal-cooling grinding surface integrity

Highlights: • Molecular dynamics method is adopted to design nanofluids. • Dispersion/adsorption behavior of ionic liquid and MWCNTs/MoS₂ is simulated. • A synergistic strengthening effect of dispersed nanofluids is investigated. • Nanofluids were characterized and applied in internal-cooling grinding. The combination of nanofluids and internal-cooling grinding was applied in machining super-alloy to solve the problem of insufficient heat transfer and lubrication, thereby improving the surface integrity. In this paper, molecular dynamics method was utilized to calculate the interaction energy and mean square displacement (MSD), and the adsorption or dispersion behavior of nanoparticles (MWCNTs, MoS₂) and ionic liquid ([EMIm]BF₄) in the base fluid (H₂O) was revealing. The centroid distance and the dynamic images indicated that the dispersion distance of 4 wt% [EMIm]BF₄-MWCNTs reaches 105.37 Å, which is the optimal ratio. In the adsorption of MWCNTs and MoS₂, it was observed that the two kinds of nanoparticles formed a pressure-bearing sandwich structure, which can synergistically enhance heat transfer and lubrication. Raman spectroscopy affirmed the modification effect of ionic liquids. Nanoparticle size and contact angle tests indicated that the optimized nanofluid has excellent dispersion and film-forming properties. In addition, nanofluids were applied to the grinding process through a pressurized internal-cooling grinding wheel. Compared with the conventional coolant, the grinding temperature of the optimized nanofluid is reduced by 9.28% and 12.89%, and the surface roughness on the workpiece is reduced by 21.34% and 23.73%, which effectively lessens the furrow and burrs.