| This dissertation presents a comprehensive thermoelastohydrodynamic (TEHD) analysis for the fluid film journal bearings. Utilizing the advanced theoretical models and numerical methods, the current analysis predicts a complete set of bearing performances including the journal operating position, maximum pad temperature and the bearing dynamic coefficients. The coupled pressure, temperature and elasticity problem is simultaneously solved via a series of iterations. The hydrodynamic pressure is calculated from the generalized Reynolds equation and a new two-dimensional energy equation is derived to calculate the temperature distribution. The pad mechanical and thermal deformations are calculated by a two-dimensional finite element method. The turbulence effects, pivot flexibility, journal and shell thermal expansions are all taken into account in the theoretical modeling. The TEHD algorithm is then applied to analyze several common industrial designs such as the fixed geometry bearing, tilting pad bearing, directly lubricated bearings and pressure dam bearing. Based on the available experimental data, a triggered turbulence theory is developed to explain the cooling mechanism for the leading edge groove bearing while a special mixing model is proposed to explain the cooling effects for the spray bar bearing. In addition to the flooded oil feed condition, theories are also developed and employed to analyze some special lubrication conditions which include axial flow, high ambient pressure and starvation. To validate the current theories, the TEHD results are extensively compared with a wide range of experimental data. Excellent agreement is generally obtained throughout the comparisons. |
