Study On Three Dimensional TEHD, Vibration And Noise Characteristics Of Thrust Bearings

As one of the key components in rotating machinery with axial heavy load, the performance of thrust bearings directly affect the stability and efficiency of the unit. As for special working environment, not only good lubrication performance, but also reasonable vibration and noise level are required. Taking the representative vertical thrust bearings in hydraulic generator set and horizontal thrust bearings in ship propulsion shafting as the research object of this thesis, universal three dimensional thermo-elasto-hydro-dynamic (TEHD) model and oil film dynamic characteristics calculation model for thrust bearings with kinds of structural types were set up. On this basis, the transmission of vibration and noise radiation characteristics of the marine thrust bearings were also studied. The major contents of this thesis consist of the following four aspects:First, taking the thrust bearing system as the research object, on the basis of comprehensively considering the influence of hydrodynamic lubrication, thermal effects and thermoelastic deformations, a three dimensional TEHD model consisting of generalized Reynolds equation, energy equation of oil film, oil film thickness equation, viscosity-temperature equation lubricating oil, solid-state heat conduction equation and solid thermoelastic deformation equation was established. At the same time, the numerical calculation method for the theoretical model was introduced in detail.Second, based on the above theoretical model, a detailed theoretical analysis of the thrust bearings with pins and double layer system used in the Three Gorges hydroelectric generators, as well as the bidirectional thrust bearings used in pump-turbines, was carried out. Meanwhile, experimental results were obtained from the HEC (Harbin Electric Machinery Co. Ltd.)3000ton thrust bearing test rig, in order to provide an evidence of validation of the three dimensional TEHD model set up in this thesis.Third, both two dimensional and three dimensional TEHD model were adopted to study the lubrication performance of marine thrust bearings, in order to verify the calculation accuracy of two dimensional model by comparison. And then first-order Taylor series method was employed to solve two dimensional Reynolds equation to obtain axial dynamic coefficients of marine thrust bearings.Fourth, the finite element and boundary element models of marine thrust bearing system were set up to analyze the influence of key parameters including dynamic characteristics of supporting structure and structural damping ratio on vibration and shell noise radiation characteristics of marine thrust bearings.Overall, theoretical analysis and experimental research methods were employed comprehensively to conduct in-depth research on the lubrication performance of thrust bearings used in hydroelectric generators and marine. Finite element method and boundary element method were also employed to evaluate the vibration transmission and noise radiation characteristics of marine thrust bearings.