The Friction Power Lossanalysis Of Hydrodynamic Bearing Rotor System Allowing For Roundness Errors

Friction power loss and dynamic characteristics of a hydrodynamic journal bearingsystem have a close relationship with the system structure parameters. Most of the researchon dynamic of hydrodynamic journal bearings is according to the design dimension withoutconsidering the influence of manufacturing tolerances. Actually, all kinds of manufacturingerrors of structure parameters affect the dynamic characteristics in different degrees.Manufacturing errors exist objectively. Thus, the manufacturing errors’ effects on dynamiccharacteristics can’t be ignored. The main purpose of this study is to discover theinfluences of roundness error on hydrodynamic journal bearings’ dynamic stability andfriction power loss. At first, the dynamic model of hydrodynamic bearing rotor system wasestablished, and the finite difference method was utilized to solve Reynolds equation toobtain oil-film pressure and oil-film load carrying capacity. The calculation method of axisorbit of Hydrodynamic bearing rotor system to which roundness errors had been taken intoconsideration and the judgment of instability onset speed was presented. The dimensionlessoperation parameter Opwas calculated to obtain the stability maps which are widelyaccepted. The stability maps of some different extent of roundness errors of system andfriction power loss maps were presented.And then, The shape of roundness errors inclusion one lobe, ellipse, three lobe aretaking into consideration, and we take different roundness errors to permutation andcombination, so nine kinds of difference roundness errors models have been get abouthydrodynamic journal bearing system. In the same time, the degree of roundness errorshave been take into consideration and formed thirty-six kinds of errors models abouthydrodynamic journal bearing system. We analyze those errors models with the theoryhave been validated, the stability maps and the friction power loss maps of hydrodynamicjournal bearing system allowing for roundness errors. The stability maps and the frictionpower loss maps for hydrodynamic journal bearing system with different roundness errorshave been analyze and correlative conclusion have been presented.Our team constructed a Hydrodynamic bearing rotor system experimental facility tovalidate whether the theoretical analysis is credible, and the experimental facility based onLabVIEW acquisition of signal system, this system can monitor and save rotor speed signal,the axis orbits of journal center signal, frequency signal and the amplitude signal ofvibration. Torque sensor can monitor torque, speed and friction power loss of whole system.Our team made four shafts with different roundness errors to validate the influences ofroundness error on hydrodynamic journal bearings’ dynamic stability and friction power loss. In the last chapter of this paper, we take notional result compare with experimentalresult. The analyzed results show good correlation between the experimental data and thenotional data, and the cause of error had been explained. The conclusion of this thesis canbe used to control errors of hydrodynamic bearing rotor system,reduce the cost ofmanufacture and cut down the friction power loss.