The lubrication process is a critical issue in preventing the degradation of the friction material, enhancing the efficiency of the brake system and reduce the wear behavior. The paper proposes a novel concept for axels dry braking system in off-road vehicles by implementing an oil recovery system in the friction plates chamber. The new system is able to remove the oil in the discs’ chamber when they are not engaged and to replenish it when the braking system is activated and the heat generated has to be dissipated. Thus, the energy losses due to the oil splashing will be significantly reduced with remarkable effects on the fuel consumption of the vehicle. Since experimental measurements are very difficult to carry out on a real system, a simplified geometry is designed and an ad-hoc test rig realized. A thermal camera is focused on the gear chamber in order to monitor the oil’s sloshing temperature. Fast imaging techniques are used to capture the multiphase flow pattern within the friction plates chamber at different rotational speeds of the axel. A direct correlation between the oil’s removal and the reduction of the torque of the electrical motor used to drive the braking system inside the test bench was highlighted. In particular, these results, applied to the real system, will lead to considerable savings in terms of mechanical power provided to the vehicle.

The experimental results are used to validate a full 3D multi-phase CFD approach. A good agreement between the measurements and the calculations is found. The fluid dynamic behavior of the oil at the two deflectors is remarkably complex to be caught experimentally, thus, CFD modeling can effectively extend the experimental acquisitions, and demonstrate the totally 3D nature of the phenomena that occurs into the gears’ chamber. The numerical modeling is therefore employed to predict the flow distribution in the real geometry and under actual operating conditions. A modular approach is adopted for the domain subdivision in order to represent accurately the three-dimensional geometrical features, while the volume of fluid approach is used to model the multi-phase flow that characterizes the component. A conjugate heat transfer model is also adopted to predict the heat transferred from the discs to the working fluid and how the fluid is dissipating the heat within the component. By means of the numerical analysis the geometry of the real system is designed in order to improve the performance of the dry braking systems both in terms of energy saving and oil cooling.


Numerical and Experimental Analysis of a Novel Concept for Axels Dry Braking System in Off-Road Vehicles

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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