Smoothed Particle Hydrodynamics Simulation of Oil-Jet Gear Interaction1

Abstract

In this paper, the complex two-phase flow during oil-jet impingement on a rotating spur gear is investigated using the meshless smoothed particle hydrodynamics (SPH) method. On the basis of a two-dimensional setup, a comparison of single-phase SPH to multiphase SPH simulations and the application of the volume of fluid method is drawn. The results of the different approaches are compared regarding the predicted flow phenomenology and computational effort. It is shown that the application of single-phase SPH is justified and that this approach is superior in computational time, enabling faster simulations. In the next step, a three-dimensional single-phase SPH setup is exploited to predict the flow phenomena during the impingement of an oil-jet on a spur gear for three different jet inclination angles. The oil’s flow phenomenology is described and the obtained resistance torque is presented. Thereby, a significant effect of the inclination angle on the oil spreading and splashing process as well as the resistance torque is identified.

CFD study of oil-jet gear interaction flow phenomena in spur gears

“…Modeling the global three-dimensional air flow (4,24) might require to use a domain with larger extents including the side walls of the gears. However, as stated in a previous work (2) , aerodynamic effects are not changing the primary oil flow on the flanks. Rotational periodicity is applied in circumferential direction for the respective planes of the inner and outer zone each.…”

“…On the confinement in radial direction of the outer zone, a pressure outlet is applied. Gravity is omitted, since its effect is negligible (1,2) . The setup contains two mesh interfaces.…”

“…Based on the baseline case (B3), the parameters are varied in three steps each. According to the relations in Equations (2) and 3, the varied parameters affect the dependent variables as , Q, and V gap . To achieve comparable kinematics, the gear speed is adapted (cases II) to retain = 0.5 after the jet velocity was varied (cases I).…”

“…Consequently, the oil is flung off by centrifugal forces. Fondelli et al (1) and Keller et al (2) present characteristic non-dimensional groups. They show that while the impingement and spreading is mainly driven by inertia forces, the film motion is driven by centrifugal, viscous, and to a lesser extent by surface tension forces.…”

“…Therefore, alternative CFD approaches have been employed. Keller et al (13,2) applied the particle-based Smoothed Particle Hydrodynamics (SPH) method to simulate the interaction between an oil-jet and a rotating gear. In a comparison to results obtained using the VOF method, consistent flow patterns were observed, substantiating the validity of the numerical predictions.…”