New Development of a Gas Cavitation Model for Evaluation of Drag Torque Characteristics in Disengaged Wet Clutches

Oil film separation and drag torque in disengaged wet brakes

“…It was also shown that a coherent film of lubricant could not be maintained between the discs under some operating conditions. Similar findings have been reported for wet clutches with a lubricant supply through a central shaft [7][8][9]. The breakdown of a coherent film of lubricant is generally attributed to onset of cavitation [6,10].…”

“…The implicit formulation shown in equation 12can then be solved iteratively to find the value of to satisfy the equation, where varies between the internal radius and the external disc radius when − < 0 .Such conditions have been shown to be plausible by experimental measurements carried out by Pahlovy et al [9]. These are shown be reasonable when the lubricant flow rate is less than the centrifugal pumping rate determined through numerical analysis conducted by Aphale et al [24].…”

Hydrodynamic Lubricant Film Separation During Codirectional and Counter-Directional Rotations of Disengaged Wet Clutch Packs

“…A diagrammatic representation Case 3 is shown in figure (1c). The calculation of is described later in equation (29). The following solution describes the pressure gradient for film separation at any radius:…”

“…This value is used to fit the rupture point of the model to the experimental data. The assumed pressure is reasonable when considering typical values for meniscus forces, and build-up of pressure in the clutch housing [29]. The running conditions are also described in [27], during which: |Ω 2 | > |Ω 1 |, as the separator plate remains stationary.…”

Efficiency of disengaged wet brake packs

“…Good conformance was obtained between the experimental results and a computational fluid dynamics model. A similar study was conducted by Pahlovy et al [11] who also measured the lubricant film pressures at the inner and the outer edges of the annular plates.…”