Pivot design and angular misalignment effects on tilting pad journal bearing characteristics: Four pads for load on pad configuration

• Film thickness formula considering journal and pads׳ angular motions is provided.
• Pad dynamic model with spherical pivot design produced self-alignment.
• Pad angular motion is simulated in accordance with varying misalignment.

This paper focuses on angular misalignment between tilting pad journal bearing (TPJB) and spinning journal. Three-dimensional (3D) TPJB numerical model is presented considering the tilt, pitch and yaw motions of the pad, pivot deformation, journal angular motion, and thermo-hydro-dynamic (THD) lubrication model. Cylindrical pivot is assumed to produce only tilting motion with a line contact, whereas the spherical pivot is to provide three angular motions with a point contact. Numerical modeling and simulation results are provided and discussed. Angular misalignment effects on bearing performance are predicted. Spherical pivot design produced invariant characteristics with varying misalignment ratio and phase, whereas the cylindrical pivot showed noticeable variation. Pad yaw and pitch motions led to the differential between the two pivot configurations.