The Influence of Grooves on the Fully Wetted and Aerated Flow Between Open Clutch Plates
- 10 December 2009
- journal article
- Published by ASME International in Journal of Tribology
- Vol. 132 (1), 011104
- https://doi.org/10.1115/1.3195037
Abstract
In a disengaged or open clutch mode, one plate rotates while the other is stationary. This speed difference between the two plates (on the order of 1000 rpm) and the small clearance between them (on the order of 100 μm) results in large velocity gradients. Transmission fluid is passed between clutches since during reengagement; this oil provides lubrication and carries heat away. However, during the disengaged mode the shearing of this oil as it passes between the plates results in viscous drag that wastes power. Introduction of air between the two plates during the disengaged mode, referred to as aeration, is the most significant way of reducing this friction drag due to low viscosity of air compared with oil. Open clutch drag reduction is enhanced by providing grooves on one of the plates since they are known to promote aeration. Yet, a continuous supply of lubrication oil is necessary, even during disengagement. This study examines the underlying processes responsible for the oil flow between grooved disks and possible aeration through a combination of experiments and numerical computations. A two-dimensional model of the three-dimensional, single-phase flow between a stationary and a rotating clutch plate is presented, which is capable of describing pressures and shear stress distribution for plates with radial grooved geometries. The computational fluid dynamics code FLUENT® is used to examine the single-phase and aerated flows between the plates. These results are compared with accompanying experimental observations. We also examine new groove designs to study their efficiency in promoting aeration. Finally, we propose reasons for grooves promoting aeration in clutches.Keywords
This publication has 7 references indexed in Scilit:
- Modeling and Parametric Study of Torque in Open Clutch PlatesJournal of Tribology, 2005
- Analysis of the Various Factors Affecting Drag Torque in Multiple-Plate Wet ClutchesSAE International Journal of Advances and Current Practices in Mobility, 2003
- CFD Simulation of the Flows Within Disengaged Wet Clutches of an Automatic TransmissionSAE International Journal of Advances and Current Practices in Mobility, 2003
- Using the SAE #2 Machine to Evaluate Wet Clutch Drag LossesSAE International Journal of Advances and Current Practices in Mobility, 1991
- Parameters Contributing to Power Loss in Disengaged Wet ClutchesSAE International Journal of Advances and Current Practices in Mobility, 1974
- Effects of Transmission Fluid on Clutch PerformanceSAE International Journal of Advances and Current Practices in Mobility, 1971
- SPIRAL GROOVE BEARINGSIndustrial Lubrication and Tribology, 1965