Effect of Various Shapes of Rough Transverse Slider Bearing Equipped with Ferro-Lubricant on the Load-Tolerating Capability by Mathematical Modeling

This paper investigates the effect of various film shapes of rough transverse slider bearing with Ferro-lubricant on the bearing system's load-tolerating capability (LTC). The current article describes the efforts to improve bearing’s LTC by using a Ferro-lubricant as a non-Newtonian fluid and choosing the bearing's (piston ring’s) proper geometrical shape in the I. C. Engine. The mathematical model and the numerical and graphical results reveal the facts about enhancing the bearing system's performance. Moreover, the adverse effect of roughness can be lessened to a certain range by growing the magnetic field's strength.

SPH modelling of hydrodynamic lubrication: laminar fluid flow–structure interaction with no-slip conditions for slider bearings

The FOSS CFD-SPH code SPHERA v.9.0.0 (RSE SpA) is improved to deal with “fluid–solid body” interactions under no-slip conditions and laminar regimes for the simulation of hydrodynamic lubrication. The code is herein validated in relation to a uniform slider bearing (i.e. for a constant lubricant film depth) and a linear slider bearing (i.e. for a film depth with a linear profile variation along the main flow direction). Validations refer to comparisons with analytical solutions, herein generalized to consider any Dirichlet boundary condition. Further, this study allows a first code validation of the “fluid–fixed frontier” interactions under no-slip conditions. With respect to the most state-of-the-art models (2D codes based on Reynolds’ equation for fluid films), the following distinctive features are highlighted: (1) 3D formulation on all the terms of the Navier–Stokes equations for incompressible fluids with uniform viscosity; (2) validations on both local and global quantities (pressure and velocity profiles; load-bearing capacity); (3) possibility to simulate any 3D topology. This study also shows the advantages of using a CFD-SPH code in simulating the inertia and 3D effects close to the slider edges, and it opens new research directions overcoming the limitations of the codes for hydrodynamic lubrication based on the Reynolds’ equation for fluid films. This study finally allows SPHERA to deal with hydrodynamic lubrication and improves the code for other relevant application fields involving fluid–structure interactions (e.g. transport of solid bodies by floods and earth landslides; rock landslides). SPHERA is developed and distributed on a GitHub public repository.

Implementation of micropolar fluids model and hydrodynamic behavior analysis using user-defined function in FLUENT

Micropolar fluids commonly represent the complex fluids with microstructure, for example, animal blood and liquid crystals. To understand the behavior of micropolar fluids and the role of micropolar parameters, different micropolar fluids models were implemented by user-defined function in the FLUENT software. The correctness of user-defined function programs was verified comparing to the analytical solution in the Poiseuille flow. Then, the hydrodynamic behavior was analyzed in the Poiseuille flow with a moving particle, slider bearing, and dam break. Numerical results show that microrotation viscosity weakens translational velocity while enhances the pressure of micropolar fluids, in addition, microrotation velocity decreases with the increase in angular viscosity.