Numerical analysis of Nano-Lubricant Effects on the Performance of a Hydrostatic Rotary Table Using ANSYS Fluent

Hydrostatic rotary tables are important part in precision machining systems due to their high load-carrying capacity, good stiffness and provide accurate positioning. The current study focused on numerical analysis of an aluminium oxide (Al_₂O_₃) water nanofluid as working fluid used in a capillary-compensated hydrostatic rotary table with a double rectangular recess design. The use of an Al₂O₃-Water nanofluid is investigated not only to increase viscosity, but to adjust the hydraulic properties of a water-based lubricant. While oil-based lubricants offer appropriate viscosity and load supporting characteristics, the present study focused on water-based lubrication applications only. A three-dimensional computational fluid dynamics (CFD) model was created and analysed using ANSYS Fluent under steady-state laminar flow conditions. The effective properties of the nanofluid were determined by using the mixture model for density and the Krieger-Dougherty model for effective dynamic viscosity. Nanoparticle volume fractions changing from 1% to 10% were considered to obtain their effect on pressure distribution, lubricant flow rate, load-carrying capacity and static stiffness. The results show that increasing the nanoparticle volume fraction increase the effective viscosity and hydraulic resistance of the capillary compensated system, which causes modifying the pressure-flow balance and pressure distribution under the given operating conditions. The obtained pressure distribution affects the load-carrying ability and static stiffness of the bearing. Thus, any observed variations in load-carrying capacity and stiffness are associated with the modified pressure distribution rather than with the viscosity as direct source of load capacity. The double rectangular recess geometry also influences the pressure distribution as well as the static performance of hydrostatic rotary table. These results provide understanding about the relationships between nanofluid characteristics, capillary effects and pressure distribution which provide a foundation for assessing the static performance of Al₂O₃-Water nanofluids in precision hydrostatic rotary tables.