Comparative stability evaluation of balanced horizontal rotor and vertical rotor mounted on tilting pad journal bearing by computing Floquet multipliers

The effect of orientation of rotor i.e., horizontal and vertical on the stability of the rotor mounted on 4-pad tilting pad journal bearing (TPJB) has been analysed. Using Timoshenko beam (TB) elements, a finite element (FE) model of the system was created with a flexible rotor in mind. Employing the short bearing estimation, the nonlinear fluid film forces (FFFs) produced in TPJBs have been analytically determined. ODE-15s solver in MATLAB®. has been used to solve the system's governing differential equations (GDE) of motion. Floquet plots has been generated by computing Floquet multipliers to show the stability condition of the system at different speeds in both horizontal rotor (HR)-TPJB and vertical rotor (VR)-TPJB configurations. Analysis show that the HR-TPJB system shows more stability than VR-TPJB system at both operational speed ranges.