Bearing Housing Design for Vibration Control, Using Tilting Pad Bearings Instead of Lemon-Bore Type on a Gas Turbine

2021 ◽  
Author(s):  
Anil Chippa ◽  
Aparna Satheesh ◽  
Marcin Bielecki ◽  
Babu Santhana Gopalakrishnan
Keyword(s):  
Vibration Control ◽  
Gas Turbine ◽  
Housing Design ◽  
Tilting Pad ◽  
Tilting Pad Bearings

Bearing Housing Design for Vibration Control, Using Tilting Pad Bearings Instead of Lemon-Bore Type on a Gas Turbine

2020 ◽  
Author(s):  
Chippa Anil ◽  
Aparna Satheesh ◽  
Babu Santhanagopalakrishnan ◽  
Marcin Bielecki
Keyword(s):  
Gas Turbine ◽  
Gas Turbines ◽  
Structural Integrity ◽  
Plane Surface ◽  
Rotor Dynamics ◽  
Turbine Rotor ◽  
Outer Diameter ◽  
Housing Design ◽  
Tilting Pad ◽  
And Performance

Abstract Heavy duty gas turbines are usually equipped with hydrodynamic bearings which are either lemon-bore or tilting pad type. Baker Hughes legacy gas turbines use these two types of bearings, and its selection is based on 1) considering pros & cons from Rotor dynamics, 2) bearing performance, 3) bearing housing stiffness, 4) vibration detection & control. Non-contact probes are used to monitor the vibrations of rotor. Majority of legacy gas turbines are not equipped with these probes. Due to this fact, over the years it resulted in non-detection of dynamics & vibration issue, which caused frequent bearing replacement. As the increase in industry demand to apply and measure vibrations using non-contact probes on bearings, an effort was made by Baker Hughes to implement these on existing fleet units. Also, in order to increase rotor dynamics stability of low-pressure rotor, to improve bearing life and performance, effort was made to replace lemon-bore bearings with tilting pad. This paper demonstrates efforts made to design the titling pad which would fit within envelop of already available bearing housing. Bearing/shaft clearance, bearing performance, modification of bearing retainer clearances are the mandatory tasks which would be dealt in this study. The swap of bearing type, and its effect on whole gas turbine rotor dynamic stability, checking the frequency crossovers with Campbell diagram would also be dealt in this paper. This paper also focuses on assessment on oil passage routing, temperature & proximity probe instrumentation routing design. Re-design is performed by analyzing various configuration, assessing different sensitivity studies & validation of modified bearing housing from structural integrity, ultimate load capability, & split plane oil leakage retention and its comparison with baseline are most important aspects of finalization of this change, which will be showcased in this paper. Instrumentation routing was a critical task when the considering bearing replacement from lemon-bore to tilting pad. As lemon-bore type bearings just have an elliptical inner surface, it’s quite easy to install the thermocouples into a simple hole. But as replacement has tilting pads, the challenge is to instrument the pads without effecting their movement and functionality. Such best practices are also dealt in this paper. Comparison of tilting-pad with lemon-bore, considering the fixed shaft diameter, the retainer outer diameter of tilting pad is higher than lemon-bore. This effect has a change in bearing seat on bearing housing, thereby reducing the effective stiffness of the housing, and the reduced split plane surface. To tackle this situation, several sensitivities were executed, by re-modifying the bolts and bolt holes on the existing housing, without modifying the housing envelop.

Experimental Determination of Dynamic Characteristics of a Full Size Gas Turbine Tilting-Pad Journal Bearing by an Impact Test Method

1991 ◽  
Author(s):  
S. H. Chan ◽  
M. F. White
Keyword(s):  
Gas Turbine ◽  
Impact Test ◽  
Journal Bearing ◽  
Estimation Procedure ◽  
Response Spectra ◽  
Test Method ◽  
Full Size ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing ◽  
The Impact

Abstract Measurements have been taken on an experimental rotor-bearing test rig which consists of a full size gas turbine shaft supported by two five-pad tilting-pad journal bearings. The impact test method was applied by exciting one end of the shaft in-situ by means of a hammer blow. Impact forces and response displacements were collected and analysed with suitable corrections for runout effect. Averaged frequency response spectra thus obtained were used in a parameter estimation procedure to calculate the dynamic coefficients of the tested tilting-pad journal bearing. An analytical single degree-of-freedom model was employed and one of the input parameters in the mechanical model, the effective mass, was found to significantly influence the estimated results. The measured stiffness and damping coefficients are compared with results predicted by a bearing design program. Possible sources of discrepancies between experimental and theoretical results are discussed.

scholarly journals Fluid Film Bearing Housing Design for a Hot Ambient Environment

1976 ◽  
Author(s):  
J. D. McHugh ◽  
W. O. Winer ◽  
G. D. Robson
Keyword(s):  
Gas Turbine ◽  
Journal Bearing ◽  
Test Facility ◽  
Experimental Program ◽  
Special Test ◽  
Housing Design ◽  
Full Size ◽  
Ambient Temperatures ◽  
Operating Field ◽  
Industrial Gas Turbine

Industrial gas turbine rotors sometimes require a journal bearing in a region of the machine surrounded by compressor discharge air. Ambient temperatures in this region may exceed 600 F (588 K), which poses a challenge to bearing designers. The present paper describes housing design approaches to meeting this challenge, an experimental program to evaluate them, and the application of results to operating field units. The experimental program was carried out in a special test facility on full-size housings for a 14-in. journal bearing in a hot, pressurized environment.

On the Thermal Effects in the Design of Tilting-Pad Bearings Subjected to Inlet Pressure Build-Up

1991 ◽  
Vol 113 (3) ◽  
pp. 526-532 ◽  
Author(s):  
K. W. Kim ◽  
C. M. Rodkiewicz
Keyword(s):  
Thermal Effects ◽  
Center Of Pressure ◽  
Load Capacity ◽  
Inlet Pressure ◽  
Maximum Temperature ◽  
Pivot Point ◽  
Temperature Distributions ◽  
Tilting Pad ◽  
Tilting Pad Bearings ◽  
Force Coordinate

The presented analytical consideration of tilting-pad bearings incorporates simultaneously the changes in viscosity (due to viscous dissipation) and in the nonambient inlet pressure (due to momentum depletion within the fore-region). The solution provides the following quantities: film temperature distributions, pressure distribution, maximum temperature of the pad, load capacity, friction force, coordinate of the center of pressure, and coordinate of the pivot point. Comparison with the case when the inlet pressure is assumed to be ambient indicates the significance of the pressure build-up in the fore-region.

Thermo-hybrid lubrication FSI-CFD model for the static characteristics of hybrid porous tilting pad bearings

2021 ◽  
pp. 107397
Author(s):  
Xiaofei Jin ◽  
Peng Xia ◽  
Zhansheng Liu ◽  
Wensheng Ma ◽  
Pu Zhang ◽  
...  
Keyword(s):  
Static Characteristics ◽  
Cfd Model ◽  
Tilting Pad ◽  
Tilting Pad Bearings

Rotordynamic characterization of tilting-pad bearings with eight pads in vertical rotors

2021 ◽  
pp. 1-20
Author(s):  
David J Rondon ◽  
Gudeta Berhanu Benti ◽  
Jan-Olov Aidanpää ◽  
Rolf Gustavsson
Keyword(s):  
Stokes Equations ◽  
Forced Response ◽  
Navier Stokes ◽  
Navier Stokes Equations ◽  
Mean Values ◽  
Stationary Coordinate System ◽  
Tilting Pad ◽  
Tilting Pad Bearings ◽  
Stiffness And Damping

Abstract It has been documented that stiffness and damping for a four-pad bearing are dependent not only the magnitude of the load but also on the position of the rotor in the bearing. However, 8-pad bearings are not commonly employed on horizontal turbines, and the presence of several pads in the bearing will decisively affect the dynamics of the system. This paper evaluates the stiffness and damping coefficients of tilting-pad bearings with eight pads and explore the main frequencies acting on the forced response of a vertical rotor. The bearing properties were modeled as a function of eccentricity and position in the stationary coordinate system by Navier-Stokes equations whose results are taken from commercial software. The simulated unbalanced response is compared to experimental results; the changing position of the shaft produces a periodic stiffness and damping, which is dependent on the number of pads. Cross-coupled coefficients influence is discussed, showing that their absence makes an accurate model for the mean values. The results indicate that simulation of vertical rotors with 8-pad bearings can be simplified which allow more effective simulations and dynamic analysis.

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