DYNAMIC CHARACTERISTICS OF TEHD TILT PAD JOURNAL BEARING SIMULATION INCLUDING MULTIPLE-MODE PAD FLEXIBILITY MODEL

An approach for incorporating the heat transfer and elastic deformatio n effects into dynamic coefficient calculation is presented. A global analysis method is used, which finds the equilibrium pad tilt angles a t each eccentricity position and includes crossfilm variable viscosity , heat transfer effects in the lubricant, elastic deformation, heat co nduction effects in the pads, and elastic deformation effect in the pi vots. Deflection modes are used to approximate deformation of the top surface of the pads. The dynamic coefficients of a single pad are calc ulated at the equilibrium state of the bearing, based on numerical per turbation with respect to the bearing degrees of freedom. These includ e journal position, pad rotation, pivot deformation, and modal coordin ates. The stiffness and damping coefficients are calculated and show v ery good agreement with experimental and numerical results from the ex isting literature.