Development and Evaluation of a Cavitation Algorithm

Abstract

A numerical procedure to predict the effects of gaseous cavitation in moderately to heavily loaded bearings is developed. The method is an outgrowth of the Elrod algorithm which is simple to w e a d which automatically implements cavitation bounda~y conditions at film rupture and refonnation. The current procedure makes w e of type dqferencing in the shear induced pow formulatioi~ to automatically switch from central to upwizd dfferences, and vice versa, at cavitation boundaries. Comparison is made with the results obtained w i n g Elrod's algorithm for variou~ test cases involving both slider and journal bearings.

Cavitation induced starvation for piston-ring/liner tribological conjunction

“…Using similar engine parameters, the minimum film thicknesses predicted by other authors are very close to the predictions of the current model: Jeng [12] (Transient Reynolds boundary conditions), Yang and Keith [21] (steady-state modified Elrod using Vijayaraghavan and Keith method [15]) and Sawicky and Yu [23] (steady-state modified Elrod using JFO boundary conditions). There is a direct correlation between film thickness and friction force magnitude.…”

“…The classic formulation of the Reynolds equation does not account for the negative pressure in the diverging part of the contact [13]. One possible solution is limiting the outlet pressures to the atmospheric pressure [14] or to the cavitation pressure [15]. Although this is a very fast method, mass conservation of the fluid flow in the cavitation region is not fulfilled.…”

“…Vijayaraghavan and Keith [15] proposed the following convenient transformation for the left hand side of equation (5):…”

“…Brewe [3] uses the Elrod algorithm to predict vapor cavitation in a submerged journal bearing during steady state and transient conditions. Vijayaraghavan and Keith [15] proposed a finite differenced scheme to predict the pressure distribution along the contact and validated the numerical results with Coyne and Elrod's experiments [20]. Yang and Keith [21] extended this approach to the piston ring lubrication, while Cioc and Keith [22] applied Elrod's algorithm using the Conservation Element (CE) and Solution Element (SE) method.…”

“…The proposed numerical model uses as a base the solution proposed by Vijayaraghavan and Keith [15] for Elrod's algorithm. However, localised contact deflection (especially in the vicinity of the dead centers) could have significant consequences for the cavitation development (this will be discussed in figure 11).…”