Rotor Dynamics in Design of a High Speed Cryogenic Pump for Geo Stationary Launch Vehicles

2014 ◽  
Author(s):  
Srinivasa R. Jammi
Keyword(s):  
High Speed ◽  
Rotor Dynamics ◽  
Rotor System ◽  
Peak Amplitude ◽  
Beam Model ◽  
Rolling Element Bearings ◽  
Launch Vehicles ◽  
Critical Speeds ◽  
Highly Nonlinear ◽  
Rolling Element

On January 5th 2014 the Indian Space Research Organization successfully launched its Geo Stationary Launch Vehicle with an indigenous Cryogenic engine. One of the main design aspects is in its rotor dynamics to predict the peak amplitude unbalance whirl and the speed at which it occurs. This engine has several key technologies, one of them specifically is coupled rotors, viz., Turbine, Hydrogen Pump and Oxidizer supported on seven nonlinear rolling element bearings and several seals all mounted in a flexible casing. The conventional beam model initially adopted failed to predict the speed at which peak unbalance response occurs. The rotor system was first developed in a solid model to determine the critical speeds of the rotor alone considering its 40000 rpm centrifugal loads with bearings treated as linear. Then, unbalance whirl of this rotor system was developed by codes specially developed for this purpose. The rolling element bearings are found to be highly nonlinear with large bearing radial forces at critical speeds. An iterative procedure was developed to match the bearing force and unbalance whirl to determine peak amplitude response speeds. Subsequently, seals and the influence of casing and internal pressures were accounted in the analysis. This paper describes the advanced rotor dynamic design of this pump.

scholarly journals Commissioning of a High Speed Composite Rotor With Hydrostatic Dampers and Ceramic Rolling Element Bearings

1993 ◽  
Author(s):  
Ross N. Headifen ◽  
Robert L. Fuller ◽  
Jon R. Kitzmiller
Keyword(s):  
High Speed ◽  
System Analysis ◽  
Rolling Element Bearings ◽  
Lumped Mass ◽  
One Dimensional ◽  
System A ◽  
Rolling Element ◽  
Speed Range ◽  
Full Speed ◽  
Stiffness And Damping

Abstract A high speed (25,000 rpm) routing machine with a 300 lb rotor was designed and manufactured. To accommodate the high shaft speed, 2.6 million DN, rolling element bearings were used with ceramic balls and inner races. In order to control the magnitude of the vibration, damping was incorporated into the system using nonrotating hydrostatic dampers. The journal for the dampers was a cylindrical cartridge that had the rolling element bearings clamped inside of it. Extensive analysis was performed on this system. A computer program was written that could model the orbit path of the lumped mass shaft in the damper over the full speed range. A second program was also written that calculated the damper nonlinear stiffness and damping coefficients, and incorporated them in with a one-dimensional beam, finite element rotordynamics model of the system. Analysis results are presented along with experimental run data from the machine. Balancing problems encountered during commissioning have limited the results to 16,500 rpm to date. The last of which is currently being remedied.

Vibration Monitoring and Damage Quantification of Faulty Ball Bearings

2005 ◽  
Vol 127 (4) ◽  
pp. 776-783 ◽  
Author(s):  
F. K. Choy ◽  
J. Zhou ◽  
M. J. Braun ◽  
L. Wang
Keyword(s):  
High Speed ◽  
Progressive Failure ◽  
Frequency Domain Analysis ◽  
Vibration Monitoring ◽  
Ball Bearings ◽  
Rolling Element Bearings ◽  
Premature Failure ◽  
Damage And Failure ◽  
Rolling Element ◽  
Safety And Reliability

More often than not, the rolling element bearings in rotating machinery are the mechanical components that are first prone to premature failure. Early warning of an impending bearing failure is vital to the safety and reliability of high-speed turbomachinery. Presently, vibration monitoring is one of the most applied procedures in on-line damage and failure monitoring of rolling element bearings. This paper presents results from an experimental rotor-bearing test rig with quantified damage induced in the supporting rolling element bearings. Both good and damaged radial and tapered ball bearings are used in this study. The vibration signatures due to damage at the ball elements and the inner race of the bearing are also examined. Vibration signature analyzing schemes such as frequency domain analysis, and chaotic vibration analysis (modified Poincare diagrams) are applied and their effectiveness in pinpoint damage are compared in this study. The size/level of the damage is corroborated with the vibration amplitudes to provide quantification criteria for bearing progressive failure prediction. Based on the results from this study, it is shown that the use of the modified Poincare map, based on the relative carrier speed, can provide an effective way for identification and quantification of bearing damage in rolling element bearings.

The Dynamic Analysis of SFD-Sliding Bearing Flexible Rotor System Based on Optimization Design

2012 ◽  
Vol 159 ◽  
pp. 355-360
Author(s):  
Ji Yan Wang ◽  
Rong Chun Guo ◽  
Xu Fei Si
Keyword(s):  
High Speed ◽  
Optimization Design ◽  
Critical Speed ◽  
Structural Parameters ◽  
Rotor System ◽  
Flexible Rotor ◽  
Optimization Analysis ◽  
Sliding Bearing ◽  
Critical Speeds ◽  
Design Variables

The paper establishes the mechanical model of SFD-sliding bearing flexible rotor system, adopting Runge-Kutta method to solve nonlinear differential equation, thus acquiring the unbalanced response curve and then gaining the first two critical speeds of the system. Meanwhile, the paper analyzes the sensitivity of the system on the first two critical speeds towards structural parameters, offering design variables to optimization analysis. Based on sensitivity analysis, genetic algorithm is employed to give an optimization analysis on critical speed, which aims to remove critical speed from working speed as much as possible. The critical speed ameliorates after the optimization which supplies theoretical basis as well as theoretical analysis towards the dynamic stability of high-speed rotor system and provides reference for the design of such rotor system.

Turbocharger rotor vibration reduction methodology with an active control scheme

2021 ◽  
pp. 095745652110307
Author(s):  
Rajasekhara Reddy Mutra ◽  
J Srinivas ◽  
Jakeer Hussain Shaik ◽  
Maddela Chinna Obaiah ◽  
Gunji Balamurali ◽  
...  
Keyword(s):  
High Speed ◽  
Active Vibration Control ◽  
Vibration Reduction ◽  
Open Loop ◽  
Rotor System ◽  
Dynamic Responses ◽  
Experimental Result ◽  
Loop Control ◽  
Highly Nonlinear ◽  
Control Configuration

The turbocharger rotors are often supported on the dual film floating ring bearings that are meant for high-speed applications. The damping ability of these bearings is relatively high. However, due to highly nonlinear bearing forces, often system instability occurs. The present work focuses on the dynamic analysis and active vibration control studies of a practical turbocharger rotor system with the use electromagnetic actuator (EMA) system. Initially, the system is analyzed using the finite element approach. The inner and outer film forces are considered along with rotor imbalance forces. The dynamic responses at the critical operating speeds are obtained numerically. To minimize the vibration amplitudes, a tiny EMA system is installed at one of the nodes along the shaft. The effect of the EMA parameters such as the number of turns of winding coil around a pole ( N c) and pole-face area ( A a) on the response of the system is studied. Further, an open-loop control configuration is practically studied by using a vibration shaker at the bearing node under different operating speeds, and the percentage reduction in critical vibration amplitudes is recorded. The EMA system is effectively controlling the high-speed rotor system vibrations. The EMA parameters N c and A a are influencing the system vibration response. Further, an experimental result has given considerable vibration reduction with the present approach.

Fault Diagnosis of High Speed Rolling Element Bearings Due to Localized Defects Using Response Surface Method

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
P. K. Kankar ◽  
Satish C. Sharma ◽  
S. P. Harsha
Keyword(s):  
Fault Diagnosis ◽  
Response Surface ◽  
Response Surface Method ◽  
High Speed ◽  
Mathematical Formulation ◽  
Rolling Element Bearings ◽  
Surface Method ◽  
Rolling Element ◽  
Rolling Elements ◽  
Localized Defects

In this paper, fault diagnosis of high speed rolling element bearings due to localized defects using response surface method has been done. The localized defects as spalls on outer race, on inner race, and on rolling elements are considered for this study. The mathematical formulation accounted for tangential motions of rolling elements and inner and outer races with the sources of nonlinearity such as Hertzian contact force and internal radial clearance. The nonlinear stiffness is obtained by the application of Hertzian elastic contact deformation theory. The mathematical formulation predicts discrete spectrum having peaks at the characteristic defect frequencies and their harmonics. Experimentation has also been performed to validate the results obtained from the mathematical model and it shows that the model can be successfully used to predict amplitude ratios among various spectral lines with localized surface defects. Combined parametric effects have been analyzed and their influence has been considered with design of experiments and surface response methodology is used to predict the dynamic response of a rotor bearing system.

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