Gearboxes are widely used in machinery to transfer power, and efficiency plays a crucial role in reducing energy consumption and pollutant emissions. But how is it possible to ensure that the machines produced are mechanically efficient and reliable? Franco Concli, professor of Mechanical Engineering at the unibz Faculty of Engineering, answered this question at the AGMA FTM2024, the Fall Technical Meeting of the American Gear Manufacturers Association that took place in Chicago in October.

To produce an efficient machine, it is important to reduce any potential source of power loss to the minimum. When rotating, gearboxes cause in fact friction, which in turn induces wear on the one hand, and heat release on the other. To reduce these effects lubricants are generally used, but defining the right quantity and the injection point is extremely challenging: too little lubricant has in fact poor lubricating effect combined with inefficient heat dissipation, while too much may cause additional power losses due to splashing. To understand the optimal type of lubrication and level of lubricant that needs to be used Professor Concli developed computational models that could simulate the effects of different lubrication conditions. In particular, he focused on different lubrication phenomena such as the foaming effect (aeration - caused by the interaction between the air system and the lubricant which promotes air trapping in the lubricant sum), oil suspension (wet windage  - where the amount of oil used is so small that it forms an aerosol that makes it efficient even at very low concentrations), and others including churning, cavitation and grease lubrication. The behaviour of an air-oil mixture is extremely difficult to predict, since it shows a behaviour that is completely different from the ones of the single constitutive phases (air and lubricant).

The system developed by the group of Professor Concli is the first able to accurately predict these physical phenomena and it dramatically reduces the computational time needed: ten years ago, 4 to 5 months where needed to compute what now the unibz research group can predict in one day. This system ensures a great balance between simulation accuracy and time efficiency and represents the future of machine design, making the construction of efficient and reliable machine a reality.