Research On Oil Film Dynamic And Vibration Reduction Characteristics Of Flexible Damping Pivot Tilting Pad Bearing

In medium and low speed cruising,the power machinery is the main source of warship noise.Ship's main power source is a turbine power system.During operation,the power turbine rotor-bearing system generates structural vibration,noise spread out through the ship base and shell,which reduces properties of ship acoustic stealth.In the modern,high-speed warship turbine power system,tilting pad bearings are widely used as the main support bearing.Tilting pad bearing oil film plays a damping effect between the rotor and the foundation.From a technical point of structural damping,this paper focuses on the flexible damping supports radial tilting pad bearing oil film dynamic and vibration reduction characteristics in the turbine system.The five aspects were included as following:(1)In bearing static equilibrium position,pad pivot force balance equation and pad motion differential equations are found.Considering temperature viscosity characteristics,the flexible damping supported tilting pad bearing frequency–reduced and full dynamics model are established.Frequency perturbation pressure and general disturbance pressure Reynolds equation are dericated.The importance of temperature viscosity characteristics is verificated using simulation case.(2)Consider fluid inertia term,flexible damping supported tilting pad bearing asynchronous dynamics coefficient,namely the frequency reduction dynamics coefficient,are analyzied.The feasibility of the static equilibrium iterative algorithm and dynamics model is tested through the emulative result and relevant literature experimental results.Using the simulation result of the equilibrium position,full dynamic coefficients are calculated.The difference between the reduced dynamics and the full dynamic coefficients of this type of bearing is compared and analysed.(3)The S damper structure is proposed.Damper structure stiffness is calculated using the finite element method.A new Newton-Raphson iterative algorithm is presented for damper-tilting pad bearing equilibrium position.When the radial direction rigidity is low,the traditional algorithm is difficult to converge.The new algorithm overcomes the shortcoming.The Comsol PDE toolkit and Matlab co-simulation method is raised.In the given load and speed conditions,full dynamic coefficients of the bearings are calculated.With different damper radial stiffness,damper-tilting pad bearing full dynamic characteristics are given.The damper-tilting pad bearing optimization design basis is provided.In this paper,the rotor-bearing dynamics and structure dynamics co-simulation method is raised.The machine feet vibration transmission characteristics of ordinary bearing,tilting pad bearing and damper-tilting pad bearing were calculated.Vibration reduction characteristics of the damper-tilting pad bearings are analysised.(4)This paper studies the oil film formation mechanism of fluid pivot tilting pad bearing in three stages.The inner hydrostatic hole and the outer hydrostatic cavity flow continuity equation.Fluid pivot tilting pad bearings outer oil film thickNess formula is established based on a pad center displacement vector method.Fluid pivot tilting pad bearings is modeling for dynamics.A new account of shaft center displacement,swing angle of pad and pad floating Newton-Raphson algorithm is presented.A hydrostatic cavity area calculation method of initial working condition is put forward.In order to choose the right parameters of bearing clearance parameters,analysis machine feet vibration performance under different bearing clearance parameters.Fluid pivot tilting pad bearings and conventional bearing supported rotor bearing foundation machine foot vibration characteristics were compared and analyzed,to verify fluid pivot tilting pad bearing vibration reduction.(5)The small proportion of bearing design with the similarity principle.Inverted bench test rig was built,fluid pivot tilting pad bearing dynamic characteristics were studied.Rotor shaft was designed with rotor modeling principle.The Large sliding bearing rotor test platform was established.Experimental vibration characteristics of fluid pivot tilting pad bearing were studied with different parameters.And with conventional bearing vibration characteristics were compared,fluid pivot tilting pad bearing vibration reduction effect was analysised.