(316ad) Lattice Boltzmann Simulation of Non-Newtonian Fluid Flows in Head Disk Interface

The simulation and modeling of non-Newtonian fluids flow are of high interest in both science and technology. Viscoelastic liquid bearing (VLB) may become a feasible alternative to slider miniaturization to fulfill further reduction in head-media spacing. In the VLB technology, an incompressible liquid film is used for the lubrication instead of conventional air bearing. Such a liquid lubrication can avoid the contact of the slider and disk, which has a very ?stiff? bearing and high shock resistance.

In this study, a three-dimensional computational tool based on lattice Boltzmann method was developed to model the non-Newtonian liquid lubrication in the head-disk interface (HDI). To facilitate the general geometry handling capabilities, the Taylor series expansion and least squares based LBM (TLLBM) was employed to simulate the liquid bearing under a model slider. Truncated power-law and Bird-Carreau models were incorporated into TLLBM to capture the non-Newtonian behavior of ultra-thin liquid film undergoing extremely high shear rates via modifying the relaxation time as a function of shear rate. After the benchmark study of Couette flow, the flow fields and pressure under the model slider were calculated for different constitutive relationships. Our LBM simulations, including clear physical pictures, an inherently transient nature, multiscale simulation capabilities, and fully parallel algorithms, could be an attractive computational tool for next generation HDI design.