Experimental and numerical investigation on thermodynamic performance of full-floating ring bearings with circumferential oil groove

摘要

Floating ring bearing systems in engine-oil lubricated turbochargers commonly withstand severe radial and axial thermal gradients. An engineered thermal management of the heat flows out of the bearing system is paramount in order to ensure the component's mechanical integrity and the reliability of the bearing systems. Therefore, oil flow plays an important role in maintaining an uninterrupted oil film and removing a large fraction of the thermal energy generated by rotational drag and the heat flow disposed from a hot shaft to cool the bearings. The floating rings usually feature circumferential oil groove on their outer surfaces for the increase of flow rate. This work presents experimental and numerical investigations into the operating parameters of full-floating ring bearings with a circumferential oil groove. A comprehensive model, including a transient form of thermal energy balance, is built to analyze relevant bearing parameters like temperature distribution, mechanical power loss, and ring speed ratio for various oil supply conditions. The Reynolds equation is solved by a separation of variables method satisfying the appropriate boundary conditions. For model validation purposes, an extensive experimental study on a cold-gas turbocharger test bench was conducted. As with the test data, the predictions show that oil supply conditions lead to different degrees of influence on the operating parameters of the investigated floating ring bearings.