scholarly journals Model and Stability Analysis of a Flexible Bladed Rotor

2006 ◽  
Vol 2006 ◽  
pp. 1-16 ◽  
Author(s):  
N. Lesaffre ◽  
J.-J. Sinou ◽  
F. Thouverez
Keyword(s):  
Stability Analysis ◽  
Rotational Inertia ◽  
Hollow Shaft ◽  
Energetic Approach ◽  
Asymmetric Rotor ◽  
Parametric Studies ◽  
Bladed Rotor ◽  
Corotational Frame ◽  
Stagger Angle ◽  
Euler Bernoulli Beam

This paper presents a fully bladed flexible rotor and outlines the associated stability analysis. From an energetic approach based on the complete energies and potentials for Euler-Bernoulli beams, a system of equations is derived, in the rotational frame, for the rotor. This later one is made of a hollow shaft modelled by an Euler-Bernoulli beam supported by a set of bearings. It is connected to a rigid disk having a rotational inertia. A full set of flexible blades is also modelled by Euler-Bernoulli beams clamped in the disk. The flexural vibrations of the blades as well as those of the shaft are considered. The evolution of the eigenvalues of this rotor, in the corotational frame, is studied. A stability detection method, bringing coalescence and loci separation phenomena to the fore, in case of an asymmetric rotor, is undertaken in order to determine a parametric domain where turbomachinery cannot encounter damage. Finally, extensive parametric studies including the length and the stagger angle of the blades as well as their flexibility are presented in order to obtain robust criteria for stable and unstable areas prediction.

scholarly journals Stability Analysis of a Flexible Bladed-Rotor

2005 ◽  
Vol 293-294 ◽  
pp. 409-416 ◽  
Author(s):  
N. Lesaffre ◽  
Jean Jacques Sinou ◽  
F. Thouverez
Keyword(s):  
Stability Analysis ◽  
High Performance ◽  
Rotational Inertia ◽  
Flexible Rotor ◽  
Energetic Approach ◽  
Asymmetric Rotor ◽  
Parametric Studies ◽  
Bladed Rotor ◽  
Stagger Angle ◽  
Made In

In any high-performance turbo-machinery, instability and damage are commonly occurring problems. The aim of this paper is to present a stability analysis of a fully-bladed flexible rotor. The flexural vibrations of the blades as well as those of the shaft are considered; the energetic approach used includes the effect of the rotational inertia. A stability detection method, bringing loci separation phenomena and coalescence, in case of an asymmetric rotor, to the fore, is made in order to determine a parametric domain where turbomachinery cannot encounter damage. Moreover, extensive parametric studies including for instance the length and the stagger angle of the blades are presented in order to obtain robust criteria for stable and unstable areas prediction. Finally, rotor/stator contact is introduced and the effect of the radial load acting on the blades when rubbing against a casing is considered.

Stability and Contact Analysis of a Flexible Bladed-Rotor

2005 ◽  
Author(s):  
Nicolas Lesaffre ◽  
Jean-Jacques Sinou ◽  
Fabrice Thouverez
Keyword(s):  
High Performance ◽  
Rotational Inertia ◽  
Hollow Shaft ◽  
Asymmetric Rotor ◽  
Parametric Studies ◽  
Bladed Rotor ◽  
Turbo Machinery ◽  
Stagger Angle ◽  
Euler Bernoulli Beam ◽  
Made In

In any high-performance turbo-machinery, instabilities and damage are commonly occurring problems. This paper presents a fully-bladed flexible rotor and outlines the associated stability analysis. Starting with the complete energies and potentials for a rotating cantilever beam in a centrifugal force field, a system of equations is derived for the rotor. This later one is made of a hollow shaft supported by a set of bearings and modelled by an Euler-Bernoulli beam connected to a rigid disk having a rotational inertia. A full set of flexible blades is also modelled by Euler-Bernoulli beams clamped in the disk. The flexural vibrations of the blades as well as those of the shaft are considered. A stability detection method, bringing coalescence and loci separation phenomena to the fore, in case of an asymmetric rotor, is made in order to determine a parametric domain where turbo-machinery cannot encounter damage. Moreover, extensive parametric studies including for instance the length and the stagger angle of the blades are presented in order to obtain robust criteria for stable and unstable areas prediction. Finally, rotor/stator contact is introduced, first with a rigid casing and then with a flexible stator. The effect of the radial load acting on the blades when rubbing against a casing is considered.

Desensitization of Axial Compressor Performance and Stability to Tip Clearance Size

2015 ◽  
Author(s):  
Engin Erler ◽  
Huu Duc Vo ◽  
Hong Yu
Keyword(s):  
Axial Compressor ◽  
Tip Clearance ◽  
Aerodynamic Stability ◽  
Tip Leakage ◽  
Compressor Rotor ◽  
Flow Features ◽  
Parametric Studies ◽  
Compressor Performance ◽  
Flow Effects ◽  
Stagger Angle

This paper presents a computational and analytical study to identify and elucidate fundamental flow features associated with the desensitization of performance and aerodynamic stability of an axial compressor rotor to tip clearance change. Parametric studies of various design change on a baseline double circular arc axial rotor led to the identification of two flow features associated with reducing sensitivity to tip clearance, namely high incoming meridional momentum in the tip region and reduction/elimination of double tip leakage. Numerical experiments were subsequently performed on the baseline rotor geometry to validate these two flow features and explain the associated flow physics by variations in incoming meridional momentum and pitch size. Finally, two designs were proposed, namely full forward chordwise sweep and partially low stagger angle, to exploit these flow features. The results indicated that both designs produce the intended flow effects and exhibit lower performance and aerodynamic stability sensitivity to tip clearance.

Application of HOHWM in the stability analysis of nonlocal Euler-Bernoulli beam

2020 ◽  
Author(s):  
Subrat Kumar Jena ◽  
Snehashish Chakraverty ◽  
Mart Ratas ◽  
Maarjus Kirs
Keyword(s):  
Stability Analysis ◽  
Bernoulli Beam ◽  
The Stability ◽  
Euler Bernoulli Beam

Desensitization of Axial Compressor Performance and Stability to Tip Clearance Size

2015 ◽  
Vol 138 (3) ◽  
Author(s):  
Engin Erler ◽  
Huu Duc Vo ◽  
Hong Yu
Keyword(s):  
Axial Compressor ◽  
Tip Clearance ◽  
Lower Sensitivity ◽  
Aerodynamic Stability ◽  
Compressor Rotor ◽  
Design Changes ◽  
Flow Features ◽  
Parametric Studies ◽  
Flow Effects ◽  
Stagger Angle

This paper presents a computational and analytical study to identify and elucidate fundamental flow features associated with the desensitization of performance and aerodynamic stability of an axial compressor rotor to tip clearance change. Parametric studies of various design changes to a baseline double circular arc airfoil axial rotor led to the identification of two flow features associated with reducing sensitivity to tip clearance, namely, high incoming meridional momentum in the tip region and reduction/elimination of double tip leakage. Numerical experiments were subsequently performed on the baseline rotor geometry to validate these two flow features and explain the associated flow physics by variations in incoming meridional momentum and pitch size. Finally, two designs were proposed, namely, a full forward chordwise sweep (FFCS) rotor and a rotor with gradual stagger angle reduction in the outer span, to exploit these flow features. The results indicated that both designs produce the intended flow effects and exhibit lower sensitivity of performance and aerodynamic stability to tip clearance.

Lateral and Torsional Vibration Analysis of Elastic Robot Manipulators With Prismatic Joint

2002 ◽  
Author(s):  
Mete Kalyoncu ◽  
Fatih M. Botsalı
Keyword(s):  
Robot Manipulator ◽  
Equations Of Motion ◽  
Rotational Inertia ◽  
Torsional Vibrations ◽  
Bending Vibrations ◽  
3 Dimensional ◽  
Prismatic Joint ◽  
Lagrange’S Equation ◽  
Runge Kutta Method ◽  
Euler Bernoulli Beam

Lateral and torsional vibrations of a robot manipulator with an elastic arm sliding in a prismatic joint are analyzed. The elastic arm is assumed as an Euler-Bernoulli beam. The mass of the end-effector is assumed as a point mass attached at the end of the elastic arm. The prismatic joint experiences 3-dimensional translational and rotational motion. The prismatic joint is assumed as rigid and frictionless. Rotational inertia of the beam is taken into consideration in obtaining the equations of motion. Elastic deformations are assumed as linear and small displacements. Axial vibrations are not considered but the effect of axial force is taken into account in the analysis. Elastic arm experiences both bending vibrations in two directions and torsional vibrations. The equations of motion are obtained by Lagrange’s equation of motion. Numerical solution of the equations of motion are obtained by Runge-Kutta method. A computer program is developed for implementation of the presented technique. Numerical simulations are presented in the form of graphics. Presented method is found to be versatile in dynamic analysis of elastic robot arms.

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