Study on critical speed of four-pad tilting-pad bearing rotor system

This article uses Dyrobes software to calculate the bearing performance and natural vibration characteristics of the rotor. The critical speed of a four pad tilting pad bearing rotor system was studied, revealing that parameters such as the oil film stiffness and damping coefficient of sliding bearings have a certain impact on the overall critical speed of the system. Through calculation and analysis, the critical speed map and corresponding critical speed of the rotor system were obtained, which helps to avoid resonance at operating speed. By calculating the critical speed under different impeller weights, it was observed that as the impeller weight increased, the first critical speed continued to decrease, but the decreasing speed gradually slowed down, providing suggestions for the stable operation of the shaft system. The relationship between the critical speed and stiffness of sliding bearings was analyzed, and it was found that within a certain speed range, a decrease in the stiffness of sliding bearings would lead to a decrease in the critical speed of the rotor. This observation provides insights for further optimizing the design of the rotor system.