Computational fluid dynamics (CFD) simulation has been widely used in the
automobile industry for design verification and validation. The article presents
the axle oil vent expulsion results from particle-based CFD simulations,
performed with a commercially available particle-based solver. The front axle
houses a differential assembly which utilizes a pinion and ring gear. The ring
gear is bolted onto the differential case in which the ring gear and
differential case are spun as a whole. The turbulent flow field of the lube oil
was simulated, and a free surface was detected. Probability density function
(PDF) distributions of local lube oil volume fractions (VFs) were used to guide
the identification of the stationary state for the simulated flow field. In the
study of vent expulsion, the lube oil temperature was varied from −12°C to 149°C
and the rotational speed of the pinion changed from 1000 rpm to 5000 rpm.
Besides the oil vent expulsion, the flow behavior, VFs, and churning power loss
predictions under different operation conditions in the axle were also
investigated. The simulation results indicate that, in general, the oil
expulsion increases with rotational speed and oil temperature, a trend validated
by experimental observations. Also discussed are the effects of the vent tube,
surface tension coefficient, and contact angle on the studied vent expulsion.
The results of the study show that the particle-based CFD method has been
successfully applied, and based on the comparison with available data, it is
reliable and computationally efficient.
