The Impact of the Cavitation Model in the Analysis of Microtextured Lubricated Journal Bearings

Abstract

In this paper, we analyze the impact of the cavitation model on the numerical assessment of lubricated journal bearings. We compare results using the classical Reynolds model and the so-called p-θ model proposed by Elrod and Adams [1974, “A Computer Program for Cavitation and Saturation Problems,” Proceedings of the First LEEDS-LYON Symposium on Cavitation and Related Phenomena in Lubrication, Leeds, UK] to fix the lack of mass conservation of Reynolds’ model. Both models are known to give quite similar predictions of load-carrying capacity and friction torque in nonstarved conditions, making Reynolds’ model the preferred model for its better numerical behavior. Here, we report on numerical comparisons of both models in the presence of microtextured bearing surfaces. We show that in the microtextured situation, Reynolds’ model largely underestimates the cavitated area, leading to inaccuracies in the estimation of several variables, such as the friction torque. This dictates that only mass-conserving models should be used when dealing with microtextured bearings.

The validity of the Reynolds equation in spool valve analysis considering cavitation

“…Half Sommerfeld condition [21], Reynolds cavitation boundary condition [15,16] and JFO (JakobssonFloberg-Olsson) condition [15,17] in a p-θ model are usually utilized in the analysis when using the Reynolds equation. And several cavitation models [19,22,23] in CFD analysis are also used.…”

An efficient adaptive finite element method algorithm with mass conservation for analysis of liquid face seals

“…These algorithms are the present algorithm (JFO-FEM), finite difference method with JFO cavitation theory (JFO-FDM) from (Ausas et al, 2007;2009) and FEM with Reynolds cavitation boundary condition (REYNOLDS-FEM). According to REYNOLDS-FEM, Uzawa's algorithm (Ito and Kunisch, 2003) was applied to assure pressure satisfying the Reynolds boundary condition.…”

“…Because the above -g model gives an unrealistic fluid film fraction (larger than 1) in the full film region for the numerical reasons from the choice of proper bulk modulus, a p-model is frequently used in various studies, where the JFO cavitation boundary is converted into a complementarity condition. According to the model, Ausas et al (2007;2009) presented an effective relaxation scheme to update the solution of satisfying complementarity conditions. Due to the capability of FEM to create a complex boundary, it was first introduced into the prediction of cavitation regions with the JFO theory by Kumar and Booker (1991; and Boedo and Booker (1995), who used Murty (1988)'s algorithm to distinguish the film rupture and reformation boundaries.…”

On the Magnitude of Load-Carrying Capacity of Textured Surfaces in Hydrodynamic Lubrication

“…The validity of the load-carrying capacity arising from the micro wedge action seems doubtful because the significant low load-carrying capacity has been determined [25,26], taking into account the mass conservation of flow between the cavitation zone and the pressure-developed zone. Therefore, the present study focuses on quantifying the extent of the load-carrying capacity enabled by the micro wedge action.…”

“…Following the development of the Elrod algorithm, several researchers revised the algorithm and used it in their studies [23,24]. Ausas et al [25] and Qiu and Khonsari [26] used the Elrod algorithm to compare the load-carrying capacity determined using the Reynolds boundary condition to that determined using the JFO theory. It was found that the load-carrying capacity is overestimated when the Reynolds boundary condition is used to consider the cavitation zone.…”