Study of Two-phase Flow and Heat Transfer Characteristics of Double Fulcrum Counter-rotating Bearing Chamber

The counter-rotation of dual rotors presents significant advantages in mitigating the gyroscopic effects inherent in aircraft engines. In this paper, a numerical investigation was conducted to analyze the flow and heat transfer characteristics within the double fulcrum bearing chamber using the CLSVOF method. Upon comparing the flow field characteristics within the bearing chamber under differing rotational directions of the high and low-pressure shafts, further investigation explored the impact of rotational speeds and bilateral oil flow rates on the flow and heat transfer characteristics of the bearing chamber. The results indicate that under counter-rotation, significant flow vortices are generated within the double fulcrum bearing chamber, causing opposing directions of wall streamlines, and thereby rendering the complexity of the flow dynamics. With increasing counter-rotating speed or speed ratio, the volume fraction of oil on the wall increases while the oil film thickness decreases. The oil film speed significantly increases. When the bilateral oil supply or oil flow rate ratio is higher, both the volume fraction of oil on the wall and the oil film thickness increase, but the increase in oil film speed is relatively small. Increasing the rotation speed and oil flow rate can enhance the wall heat transfer coefficient.