Tilting-Pad Journal Bearings With Electronic Radial Oil Injection

1998 ◽  
Vol 120 (3) ◽  
pp. 583-594 ◽  
Author(s):  
I. F. Santos ◽  
F. H. Russo
Keyword(s):  
Hydrodynamic Lubrication ◽  
Hydrodynamic Forces ◽  
Journal Bearings ◽  
Theoretical Treatment ◽  
Bearing Surface ◽  
Static Behavior ◽  
Tilting Pad ◽  
Surface Active ◽  
Oil Injection ◽  
Tilting Pad Journal Bearings

This paper gives a theoretical treatment of the problem of journal bearings modeling connected to electronic oil injection into the bearing gap. The feasibility of influencing the static behavior of hydrodynamic forces by means of such oil injection is investigated. The lubricant is injected into the bearing gap by two mechanisms of lubrication: the conventional hydrodynamic lubrication and through orifices distributed along the bearing surface (active lubrication in the radial direction). By controlling the pressure of the oil injection, it is possible to get large variations in the active hydrodynamic forces; such effects could be useful for reducing vibrations in rotating machines.

THD Analysis in Tilting-Pad Journal Bearings Using Multiple Orifice Hybrid Lubrication

1999 ◽  
Vol 121 (4) ◽  
pp. 892-900 ◽  
Author(s):  
I. F. Santos ◽  
R. Nicoletti
Keyword(s):  
Load Capacity ◽  
Flow Behavior ◽  
Journal Bearings ◽  
Operational Conditions ◽  
Tilting Pad ◽  
Bearing Load ◽  
Cooling Effects ◽  
Experimental Values ◽  
Oil Injection ◽  
Tilting Pad Journal Bearings

Tilting pad journal bearings (TPJB) using multiple orifice hybrid lubrication are analyzed applying a thermohydrodynamic (THD) theory. Adiabatic boundary conditions are adopted, and a two-dimensional model is used to represent the fluid flow behavior in the bearing gap. The influence of operational conditions on the temperature distribution and on the bearing load capacity is discussed and compared to theoretical and experimental values for a conventional hydrodynamic case (without radial oil injection). To improve the cooling effects, as well as rotor attitudes, the best location for orifices is the area near the pad edges.

Modeling of Flexible Tilting Pad Journal Bearings With Radial Oil Injection

2008 ◽  
Author(s):  
Asger M. Haugaard ◽  
Ilmar F. Santos
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Dynamic Properties ◽  
Journal Bearings ◽  
System Of Equations ◽  
Servo Valve ◽  
Tilting Pad ◽  
Dimensional Finite Element ◽  
Oil Injection ◽  
Tilting Pad Journal Bearings

The static and dynamic properties of tilting-pad journal bearings with controllable radial oil injection are investigated. The tilting pads are modelled as flexible structures and their dynamics are described using a three dimensional finite element framework and linear elasticity. The oil film pressure and flow are considered to follow the modified Reynolds equation, which includes the contribution from controllable radial oil injection. The Reynolds equation is solved using a two dimensional finite element mesh. The rotor is considered to be rigid. The servo-valve flow is governed by a second order ordinary differential equation, where the right hand side is controlled by an electronic input signal. The constitutive flow pressure relationship of the injection nozzles is that of a fully developed laminar velocity profile and the servo-valve is introduced into the system of equations by a volume conservation consideration. The Reynolds equation is linearized with respect to displacements and velocities of the nodal degrees of freedom. When all nodal points satisfy the static equilibrium condition, the system of equations is dynamically perturbed and subsequently condensed to a 2 by 2 system, keeping only the lateral motion of the rotor. As expected, rotor stability is heavily influenced by the control parameters.

Elastohydrodynamics Applied to Active Tilting-Pad Journal Bearings

2010 ◽  
Vol 132 (2) ◽  
Author(s):  
Asger M. Haugaard ◽  
Ilmar F. Santos
Keyword(s):  
Finite Element ◽  
Reynolds Equation ◽  
Dynamic Properties ◽  
Flexible Structures ◽  
Journal Bearings ◽  
System Of Equations ◽  
Tilting Pad ◽  
Dimensional Finite Element ◽  
Oil Injection ◽  
Tilting Pad Journal Bearings

The static and dynamic properties of tilting-pad journal bearings with controllable radial oil injection are investigated theoretically. The tilting pads are modeled as flexible structures and their behavior is described using a three-dimensional finite element framework and linear elasticity. The oil film pressure and flow are considered to follow the modified Reynolds equation, which includes the contribution from controllable radial oil injection. The Reynolds equation is solved using a two-dimensional finite element mesh. The rotor is considered to be rigid in terms of shape and size, but lateral movement is permitted. The servovalve flow is governed by a second order ordinary differential equation, where the right hand side is controlled by an electronic input signal. The constitutive flow-pressure relationship of the injection orifices is that of a fully developed laminar velocity profile and the servovalve is introduced into the system of equations by a mass conservation consideration. The Reynolds equation is linearized with respect to displacements and velocities of the nodal degrees of freedom. When all nodal points satisfy static equilibrium, the system of equations is dynamically perturbed and subsequently condensed to a 2×2 system, keeping only the lateral motion of the rotor. As expected, bearing dynamic coefficients are heavily influenced by the control parameters and pad compliance.

A new dynamic mesh algorithm for studying the 3D transient flow field of tilting pad journal bearings

2016 ◽  
Vol 230 (12) ◽  
pp. 1470-1482 ◽  
Author(s):  
Mengxuan Li ◽  
Chaohua Gu ◽  
Xiaohong Pan ◽  
Shuiying Zheng ◽  
Qiang Li
Keyword(s):  
Flow Field ◽  
Equilibrium Position ◽  
Transient Flow ◽  
Journal Bearings ◽  
Dynamic Mesh ◽  
Static Equilibrium ◽  
Time Step ◽  
Tilting Pad ◽  
Grid Nodes ◽  
Tilting Pad Journal Bearings

A new dynamic mesh algorithm is developed in this paper to realize the three-dimensional (3D) computational fluid dynamics (CFD) method for studying the small clearance transient flow field of tilting pad journal bearings (TPJBs). It is based on a structured grid, ensuring that the total number and the topology relationship of the grid nodes remain unchanged during the dynamic mesh updating process. The displacements of the grid nodes can be precisely recalculated at every time step. The updated mesh maintains high quality and is suitable for transient calculation of large journal displacement in FLUENT. The calculation results, such as the static equilibrium position and the dynamic characteristic coefficients, are consistent with the two-dimensional (2D) solution of the Reynolds equation. Furthermore, in the process of transient analysis, under conditions in which the journal is away from the static equilibrium position, evident differences appear between linearized and transient oil film forces, indicating that the nonlinear transient calculation is more suitable for studying the rotor-bearing system.

scholarly journals Characterization of High-Power Turbomachinery Tilting Pad Journal Bearings: First Results Obtained on a Novel Test Bench

Lubricants ◽  
2018 ◽  
Vol 6 (1) ◽  
pp. 4 ◽  
Author(s):  
Enrico Ciulli ◽  
Paola Forte ◽  
Mirko Libraschi ◽  
Lorenzo Naldi ◽  
Matteo Nuti
Keyword(s):  
High Power ◽  
Test Bench ◽  
Journal Bearings ◽  
Tilting Pad ◽  
First Results ◽  
Tilting Pad Journal Bearings

Numerical and experimental study on the dynamic bearing properties of a four-pad and eight-pad tilting pad journal bearings in a vertical rotor

2021 ◽  
pp. 1-24
Author(s):  
Gudeta Berhanu Benti ◽  
David Jose Rondon ◽  
Rolf Gustavsson ◽  
Jan-Olov Aidanpää
Keyword(s):  
Dynamic Properties ◽  
Mean Value ◽  
Journal Bearings ◽  
Navier Stokes ◽  
Rigid Rotor ◽  
Navier Stokes Equation ◽  
Vertical Rotor ◽  
Tilting Pad ◽  
Fifth Order ◽  
Tilting Pad Journal Bearings

Abstract In this paper, the dynamics of tilting pad journal bearings with four and eight pads are studied and compared experimentally and numerically. The experiments are performed on a rigid vertical rotor supported by two identical bearings. Two sets of experiments are carried out under similar test setup. One set is performed on a rigid rotor with two four-pad bearings, while the other is on a rigid rotor with two eight-pad bearings. The dynamic properties of the two bearing types are compared with each other by studying the unbalance response of the system at different rotor speeds. Numerically, the test rig is modeled as a rigid rotor and the bearing coefficients are calculated based on Navier-Stokes equation. A nonlinear bearing model is developed and used in the steady state response simulation. The measured and simulated displacement and force orbits show similar patterns for both bearing types. Compared to the measurement, the simulated mean value and range (peak-to-peak amplitude) of the bearing force deviate with a maximum of 16 % and 38 %, respectively. It is concluded that, unlike the eight-pad TPJB, the four-pad TPJB excite the system at the third and fifth-order frequencies, which are due to the number of pads, and the amplitudes of these frequencies increase with the rotor speed.

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