scholarly journals Nonlinear Dynamics Analysis of Tilting Pad Journal Bearing-Rotor System

2011 ◽  
Vol 18 (1-2) ◽  
pp. 45-52 ◽  
Author(s):  
Jiayang Ying ◽  
Yinghou Jiao ◽  
Zhaobo Chen
Keyword(s):  
Nonlinear Dynamics ◽  
System Dynamics ◽  
Journal Bearing ◽  
Rotor System ◽  
Moment Of Inertia ◽  
Dynamics Analysis ◽  
Tilting Pad ◽  
Rotor Bearing ◽  
Tilting Pad Journal Bearing ◽  
Bearing System

The nonlinear dynamics theory is increasingly applied in the dynamics analysis of tilting pad journal bearing-rotor system. However, extensive work on system dynamics done previously neglects the influence caused by the moment of inertia of the pad. In this paper, a comparison is made between the responses of the rotor in the bearings with and without pad inertia effect. Taking the Jeffcott rotor system as an example, the characteristics of bearing-rotor system, such as bifurcation diagram, cycle response, frequency spectrum, phase trajectories, and Poincaré maps, were attained within a certain rotation rate range. The pivotal oil-film force of tilting pad journal bearing was calculated by database method. The results directly demonstrate that considering the influence of the pad moment of inertia, system dynamics characteristics are found more complicated when rotor-bearing system works around natural frequency and system bifurcation is observed forward when rotor-bearing system works on high-speed range.

Dynamic Behavior Analysis of Three-Span Rotor-Bearing System with Rub-Impact Fault

2012 ◽  
Vol 460 ◽  
pp. 160-164 ◽  
Author(s):  
Song He Zhang ◽  
Yue Gang Luo ◽  
Bin Wu ◽  
Bang Chun Wen
Keyword(s):  
Nonlinear Dynamics ◽  
Behavior Analysis ◽  
Dynamic Model ◽  
Dynamic Behavior ◽  
Rotor System ◽  
System Response ◽  
Rotor Bearing ◽  
Set Up ◽  
Bearing System ◽  
Main Influence

The dynamic model of the three-span rotor-bearing system with rub-impact fault was set up. The influence to nonlinear dynamics behaviors of the rotor-bearing system that induced by rub-impact of one disc, two discs and three discs were numerically studied. The main influence of the rotor system response by the rub-impact faults are in the supercritical rotate speed. There are mutations of amplitudes in the responses of second and third spans in supercritical rotate speed when rub-impact with one disc, and there are chaotic windows in the response of first span, and jumping changes in second and third spans when rub-impact with two or three discs.

Stability Analysis of an Industrial Gas Compressor Supported by Tilting-Pad Bearings Under Different Lubrication Regimes

2011 ◽  
Author(s):  
Alejandro Cerda Varela ◽  
Ilmar Ferreira Santos
Keyword(s):  
Stability Analysis ◽  
Dynamic Behavior ◽  
Journal Bearing ◽  
Lubrication Regimes ◽  
Lubrication Regime ◽  
Stable Operating ◽  
Tilting Pad ◽  
The Stability ◽  
Tilting Pad Journal Bearing ◽  
Bearing System

This work is aimed at theoretically study the dynamic behavior of a rotor-tilting pad journal bearing system under different lubrication regimes, namely thermohydrodynamic (THD), elastohydrodynamic (EHD) and hybrid lubrication regime. The rotor modeled corresponds to an industrial compressor. Special emphasis is put on analyzing the stability map of the rotor when the different lubrication regimes are included into the TPJB modeling. Results show that, for the studied rotor, the inclusion of a THD model is more relevant when compared to an EHD model, as it implies a reduction on the instability onset speed for the rotor. Also, results show the feasibility of extending the stable operating range of the rotor by implementing a hybrid lubrication regime.

A Systematic Design of Tilting Pad Journal Bearing for a 1.2MW Turboblower

2011 ◽  
Vol 110-116 ◽  
pp. 2268-2276
Author(s):  
Hyeonmin Jo ◽  
Chaesil Kim ◽  
Sooyong Cho
Keyword(s):  
High Speed ◽  
High Efficiency ◽  
Journal Bearing ◽  
General Purpose ◽  
Rotor System ◽  
Systematic Design ◽  
Tilting Pad ◽  
Fluid Properties ◽  
Bearing Design ◽  
Tilting Pad Journal Bearing

Studies on bearing properties have been carried out to develop a rotor system with improved high-speed stability and high efficiency. However, there have been few presentations on systematic design of a tilting pad journal bearing with analysis of rotor vibration and fluid properties. Therefore, this paper presents a method to systematically design a tilting pad journal bearing, where stability of the rotor system is taken into consideration, using the general-purpose software, ARMD. This paper describes the bearing design process, which meets the conditions of 0.12mm-bearing clearance and metal temperature below 75°C.

Suppression of Rotor-Bearing System Vibrations Through Flexible Bearing Support Damping

1976 ◽  
Vol 98 (3) ◽  
pp. 1053-1061
Author(s):  
J. M. Tessarzik ◽  
T. Chiang ◽  
R. H. Badgley
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Amplitude Distribution ◽  
Random Vibrations ◽  
Response Characteristics ◽  
Response Data ◽  
Power Spectral ◽  
Tilting Pad ◽  
Rotor Bearing ◽  
Bearing System

A bearing damper, operating on the support flexure of a pivoted pad in a tilting-pad type gas-lubricated journal bearing, has been designed, built, and tested under externally applied random vibrations. A 36,000 rpm, 10 Kwe turbogenerator had previously been subjected to external random vibrations, and vibration response data had been recorded and analyzed for amplitude distribution and frequency content at a number of locations in the machine. Based upon data from that evaluation, a piston-type damper was designed and developed for each of the two flexibly-supported journal bearing pads (one in each of the two three-pad bearings). A modified turbogenerator, with dampers installed, has been retested under random vibration conditions. Root-mean-square vibration amplitudes were determined from the test data, and displacement power spectral density analyses have been performed. Results of these data reduction efforts have been compared with vibration tolerance limits and previously reported response characteristics of the unmodified machine. Results of the tests indicate significant reductions in vibration levels in the bearing gas-lubricant films, particularly in the rigidly mounted pads. The utility of the gas-lubricated damper for limiting rotor-bearing system vibrations in high-speed turbomachinery has thus been demonstrated.

Linear Stability Analysis of a Tilting-Pad Journal Bearing System

2006 ◽  
Vol 129 (2) ◽  
pp. 348-353 ◽  
Author(s):  
Guang Qiao ◽  
Liping Wang ◽  
Tiesheng Zheng
Keyword(s):  
Linear Stability ◽  
Degrees Of Freedom ◽  
Journal Bearing ◽  
Critical Mass ◽  
Dynamic Coefficients ◽  
Tilting Pad ◽  
Assembly Technique ◽  
The Stability ◽  
Tilting Pad Journal Bearing ◽  
Bearing System

This paper describes a mathematical model to study the linear stability of a tilting-pad journal bearing system. By employing the Newton-Raphson method and the pad assembly technique, the full dynamic coefficients involving the shaft degrees of freedom as well as the pad degrees of freedom are determined. Based on these dynamic coefficients, the perturbation equations including self-excited motion of the rotor and rotational motion of the pads are derived. The complex eigenvalues of the equations are computed and the pad critical mass identified by eigenvalues can be used to determine the stability zone of the system. The results show that some factors, such as the preload coefficient, the pivot position, and the rotor speed, significantly affect the stability of tilting-pad journal bearing system. Correctly adjusting those parameter values can enhance the stability of the system. Furthermore, various stability charts for the system can be plotted.

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