The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings: Part I — Theory

2006 ◽  
Author(s):  
Niels Heinrichson ◽  
Ilmar Ferreira Santos ◽  
Axel Fuerst
Keyword(s):  
High Pressure ◽  
Numerical Model ◽  
Reynolds Equation ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Model Based ◽  
Pressure Injection ◽  
Tilting Pad ◽  
High Pressure Injection

This is Part I of a two-part series of papers describing the effects of high pressure injection pockets on the operating conditions of tilting-pad thrust bearings. A numerical model based on the Reynolds equation is developed extending the three dimensional thermo-elasto-hydrodynamic (TEHD) analysis of tilting-pad thrust bearings to include the effects of high pressure injection and recesses in the bearing pad. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. It is shown that a shallow pocket positively influences the performance of the bearing as it has characteristics similar to those of a parallel step bearing.

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings—Part I: Theory

2007 ◽  
Vol 129 (4) ◽  
pp. 895-903 ◽  
Author(s):  
Niels Heinrichson ◽  
Ilmar Ferreira Santos ◽  
Axel Fuerst
Keyword(s):  
High Pressure ◽  
Three Dimensional ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Pressure Injection ◽  
Pressure Profiles ◽  
Tilting Pad ◽  
Oil Injection ◽  
High Pressure Injection ◽  
Theoretical Results

This is Part I of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. In Part I a numerical model based on the Reynolds equation is developed extending the three-dimensional thermoelastohydrodynamic (TEHD) analysis of tilting-pad thrust bearings to include the effects of high-pressure injection and recesses in the bearing pads. The model is applied to the analysis of an existing bearing of large dimensions and the influence of the pocket is analyzed. In the analysis, the high-pressure oil injection used for hydrostatic jacking is turned off (i.e., only the effect of the pocket is studied). It is shown that a shallow pocket positively influences the performance of the bearing because it has characteristics similar to those of a Rayleigh-step bearing. In Part II of the paper (Heinrichson, N., Fuerst, A., and Santos, I. F., 2007, ASME J. Tribol., 129(4), pp. 904–912) measurements of pressure profiles and oil film thickness for a test-pad are compared to theoretical results. The analysis of Part II deals both with flow situations, where the high-pressure injection is turned off, as well as with situations where it is turned on for hydrostatic jacking.

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings—Part II: Comparison Between Theory and Experiment

2007 ◽  
Vol 129 (4) ◽  
pp. 904-912 ◽  
Author(s):  
Niels Heinrichson ◽  
Axel Fuerst ◽  
Ilmar Ferreira Santos
Keyword(s):  
High Pressure ◽  
Film Thickness ◽  
Pressure Distribution ◽  
The Other ◽  
Oil Film ◽  
Thrust Bearings ◽  
Pressure Injection ◽  
Tilting Pad ◽  
Oil Injection ◽  
High Pressure Injection

This is Part II of a two-part series of papers describing the effects of high-pressure injection pockets on the operating conditions of tilting-pad thrust bearings. The paper has two main objectives. One is an experimental investigation of the influence of an oil injection pocket on the pressure distribution and oil film thickness. Two situations are analyzed: (i) when the high-pressure oil injection is turned off and (ii) when the high-pressure injection is turned on. The other objective is to validate a numerical model with respect to its ability to predict the influence of such a pocket (with and without oil injection) on the pressure distribution and oil film thickness. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of ∼100cm2 surface area. Two pads are measured in a laboratory test rig at loads of ∼1.5MPa and ∼4.0MPa and velocities of up to 33m∕s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading-edge taper. The measurements are compared to theoretical values obtained using a three-dimensional thermoelastohydrodynamic (TEHD) numerical model. At the low load, the theoretical pressure distribution corresponds well with the measured values for both pads, although the influence of the pocket is slightly underestimated. At the high load, large discrepancies exist for the pad with an injection pocket. It is argued that the discrepancies are due mainly to geometric inaccuracies of the collar surface, although they may to some extent be due to the simplifications employed in a Reynolds equation description of the pocket flow. The measured and theoretical values of oil film thickness compare well at low loads and velocities. At high loads and velocities, discrepancies grow to up to 25%. This is due to the accuracy of the measurements. When using hydrostatic jacking the model predicts the start-up behavior well.

The Influence of Injection Pockets on the Performance of Tilting-Pad Thrust Bearings: Part II — Comparison Between Theory and Experiment

2006 ◽  
Author(s):  
Niels Heinrichson ◽  
Axel Fuerst ◽  
Ilmar Ferreira Santos
Keyword(s):  
Film Thickness ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Leading Edge ◽  
Operating Conditions ◽  
Oil Film ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
High Pressure Injection ◽  
Theoretical Pressure

This is Part II of a two-part series of papers describing the effects of high pressure injection pockets on the operating conditions of tilting-pad thrust bearings. Measurements of the distribution of pressure and oil film thickness are presented for tilting-pad thrust bearing pads of approximately 100 cm2 surface area. Two pads are measured in a laboratory test-rig at loads of approximately 0.5, 1.5 and 4.0 MPa and velocities of up to 33 m/s. One pad has a plain surface. The other pad has a conical injection pocket at the pivot point and a leading edge taper. The measurements are compared to theoretical values obtained using a three dimensional thermoelasto-hydrodynamic (TEHD) numerical model. At low and intermediate loads the theoretical pressure distribution corresponds well to the measured values for both pads although the influence of the pocket is slightly underestimated. At high loads large discrepancies exist for the pad with an injection pocket. It is argued that this is likely to be due to the unevenness of the collar surface. The measured and theoretical values of oil film thickness compare well at low loads. At high loads discrepancies grow to up to 25 %. It is argued that this is due to the accuracy of the measurements.

A Comprehensive Thermodynamic Approach to Acoustic Cavitation Simulation in High-Pressure Injection Systems by a Conservative Homogeneous Barotropic-Flow Model

2003 ◽  
Author(s):  
Andrea E. Catania ◽  
Alessandro Ferrari ◽  
Michele Manno ◽  
Ezio Spessa
Keyword(s):  
High Pressure ◽  
Wave Propagation ◽  
Numerical Model ◽  
Acoustic Cavitation ◽  
Injection System ◽  
Thermodynamic Approach ◽  
Pure Liquid ◽  
Model Assessment ◽  
Pressure Injection ◽  
High Pressure Injection

A general conservative numerical model for simulation of transmission-line unsteady fluid-dynamics has been developed and applied to high-pressure injection systems. A comprehensive thermodynamic approach for modeling acoustic cavitation, i.e. cavitation induced by wave propagation, was proposed on the basis of a homogeneous barotropic mixture model of a pure liquid in equilibrium with its vapor and a gas, both dissolved and undissolved. For the pure liquid flow simulation outside the cavitation regions, or in the absence of these, temperature variations due to compressibility effects were taken into account, for the first time in injection system simulation, through a thermodynamic state equation which was derived from energy considerations. Nevertheless, in the cavitation regions, an isothermal flow was retained which is consistent with negligible thermal effects due to vaporization because of the tiny amounts of liquid involved. A novel implicit, conservative, one step, symmetrical and trapezoidal scheme of the second-order accuracy was applied to solve the hyperbolic partial differential equations governing the pipe flows. It can also be enhanced at a high-resolution level. The numerical model was applied to wave propagation and cavitation simulation in a high-pressure injection system of the pump-line-nozzle type for light and medium duty vehicles. The system was of relevance to the model assessment because it presented severely cavitating flow conditions. The predicted pressure time histories at two pipe locations and injector needle lift were compared to experimental results, substantiating the validity and robustness of the developed conservative model in simulating cavitation inception and desinence with great degree of accuracy. Cavitation transients and the flow discontinuities induced by them were numerically analyzed and discussed.

TEHD analysis of a bidirectional thrust bearing in a pumped storage unit

2016 ◽  
Vol 68 (3) ◽  
pp. 315-324 ◽  
Author(s):  
Liming Zhai ◽  
Zhengwei Wang ◽  
Yongyao Luo ◽  
Zhongjie Li
Keyword(s):  
Thrust Bearing ◽  
Three Dimensional ◽  
Elastic Equilibrium ◽  
Operating Conditions ◽  
Storage Unit ◽  
Content Type ◽  
Thrust Bearings ◽  
Tilting Pad ◽  
Lubrication Characteristics ◽  
Pumped Storage

Purpose The purpose of this paper is to analyze lubrication characteristics of a bidirectional thrust bearing in a pumped storage, considering the effect of the thermal elastic deformation of the pad and collar. Design/methodology/approach This study used the fluid–solid interaction (FSI) technique to investigate the lubrication characteristics of a bidirectional thrust bearing for several typical operating conditions. The influences of the operating conditions and the thrust load on the lubrication characteristics were analyzed. Then, various pivot eccentricities were investigated to analyze the effects of the pivot position. Findings It is found that the effect of the radial tilt angle of the collar runner on the oil film is compensated for by the radial tilt of the pad. The central pivot support system is the main factor limiting the loads of bidirectional thrust bearings. Originality/value This paper has preliminarily revealed the lubrication mechanism of bidirectional tilting-pad thrust bearings. A three-dimensional FSI method is suggested to evaluate the thermal–elastic–hydrodynamic deformations of thrust bearings instead of the conventional method, which iteratively solves the Reynolds equation, the energy equation, the heat conduction equation and the elastic equilibrium equation.

scholarly journals Run-Up Simulation of a Semi-Floating Ring Supported Turbocharger Rotor Considering Thrust Bearing and Mass-Conserving Cavitation

Lubricants ◽  
2021 ◽  
Vol 9 (4) ◽  
pp. 44
Author(s):  
Christian Ziese ◽  
Cornelius Irmscher ◽  
Steffen Nitzschke ◽  
Christian Daniel ◽  
Elmar Woschke
Keyword(s):  
Reynolds Equation ◽  
Energy Equation ◽  
Thrust Bearing ◽  
Three Dimensional ◽  
Reliable Prediction ◽  
Two Phase ◽  
Hydrodynamic Bearings ◽  
Thrust Bearings ◽  
Run Up ◽  
The Impact

The vibration behaviour of turbocharger rotors is influenced by the acting loads as well as by the type and arrangement of the hydrodynamic bearings and their operating condition. Due to the highly non-linear bearing behaviour, lubricant film-induced excitations can occur, which lead to sub-synchronous rotor vibrations. A significant impact on the oscillation behaviour is attributed to the pressure distribution in the hydrodynamic bearings, which is influenced by the thermo-hydrodynamic conditions and the occurrence of outgassing processes. This contribution investigates the vibration behaviour of a floating ring supported turbocharger rotor. For detailed modelling of the bearings, the Reynolds equation with mass-conserving cavitation, the three-dimensional energy equation and the heat conduction equation are solved. To examine the impact of outgassing processes and thrust bearing on the occurrence of sub-synchronous rotor vibrations separately, a variation of the bearing model is made. This includes run-up simulations considering or neglecting thrust bearings and two-phase flow in the lubrication gap. It is shown that, for a reliable prediction of sub-synchronous vibrations, both the modelling of outgassing processes in hydrodynamic bearings and the consideration of thrust bearing are necessary.

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