Study on the Seismic Response of High-Speed Rotational Disk-Shaft System

2012 ◽  
Author(s):  
Tomohiro Ito ◽  
Masayoshi Hatta ◽  
Atsuhiko Shintani ◽  
Chihiro Nakagawa
Keyword(s):  
Seismic Response ◽  
Seismic Wave ◽  
High Speed ◽  
Equations Of Motion ◽  
Rotating Disk ◽  
Seismic Responses ◽  
Shaft System ◽  
High Speed Rotation ◽  
Gyroscopic Effects ◽  
Response Behaviors

Recently, huge earthquakes occurred in the world, such as Great East Japan Earthquake in Japan or huge earthquake in New Zealand in 2011. In Niigata-ken Chuetsuoki earthquake in 2007, turbine blade collisions with the casing were found. Therefore, it is very important to clarify the seismic response behaviors of the high-speed rotational shaft like turbine shafts, because high-speed rotation will cause characteristic dynamic effects, such as gyro moment. In this study, seismic responses of a disk-shaft system are evaluated analytically. The disk-shaft system is treated as an elastic shaft with a rigid disk. In this analysis, gyroscopic effects of a rotating disk are also considered. Equations of motion are derived for the translational and rotational motions when the system is subjected to both horizontal and vertical seismic excitations. Response behaviors of a rotating disk-shaft system are evaluated for sinusoidal excitations and seismic wave excitations. In the sinusoidal excitations, excitation frequencies and rotational speed are varied, and in the seismic wave excitations, seismic responses are evaluated for the waves with various predominant frequencies.

Basic Study on the Seismic Response of the High-Speed Rotational Body Supported by Fluid Film Bearings

2011 ◽  
Author(s):  
Masayoshi Hatta ◽  
Atsuhiko Shintani ◽  
Tomohiro Ito
Keyword(s):  
High Speed ◽  
Seismic Waves ◽  
Equations Of Motion ◽  
Rotating Disk ◽  
Fluid Film ◽  
Basic Study ◽  
Fluid Forces ◽  
Shaft System ◽  
Fluid Film Bearings ◽  
Response Behaviors

In this study, the seismic responses of a disk and a shaft are evaluated analytically. In an analytical model, the disk-shaft system is treated as an elastic shaft with a rigid disk, and the shaft is supported by fluid film bearings. Furthermore, the gyroscopic effect of a disk and the fluid forces due to fluid film bearings are considered. The equations of motion are derived for the translational and rotational motions when the floor is subjected to horizontal and vertical excitations. The displacements of the centers of the disk and the shaft are evaluated by numerical simulations. At first, the response behaviors of a rotating disk without base excitation are evaluated, and at second, the effects of sinusoidal base excitations are investigated. Finally, the response behaviors of this system are subjected to seismic waves of varying frequencies. The results of the different seismic wave input are studied.

Parametric resonances for torsional vibration of excited rotating machineries with nonconstant velocity joints

2017 ◽  
Vol 24 (15) ◽  
pp. 3262-3277 ◽  
Author(s):  
Masoud SoltanRezaee ◽  
Mohammad-Reza Ghazavi ◽  
Asghar Najafi
Keyword(s):  
Torsional Vibration ◽  
High Speed ◽  
Power Transmission ◽  
Equations Of Motion ◽  
Monodromy Matrix ◽  
Parametric Instability ◽  
Constant Input ◽  
Inertia Moment ◽  
Disk Model ◽  
Shaft System

The shaft system is a rotating machinery with many applications due to its high speed. The angle between shafts may not be zero. So the shafts can be connected to each other through a nonconstant velocity U-joint, which transforms a constant input angular velocity into a periodically fluctuating velocity. Consequently, the mechanism is parametrically excited and may face resonance conditions. Herein, a power transmission system including three elastic shafts is considered. The polar inertia moment of each shaft is modeled as a dynamic system with two discrete disks at the shaft ends. The equations of motion consist of a set of Mathieu–Hill differential equations with periodic coefficients. The dynamic stability and torsional vibration of the shaft system are analyzed. The system geometry and inertia moment effect are the main issues in this contribution. Parametric instability charts are achieved via the monodromy matrix technique. The graphical numerical results are validated with the frequency analytical results. Finally, the stability regions are shown in the parameter spaces of velocity, misalignment angles and the inertia of disks. The results demonstrated that by changing the system inertia and geometry, stabilizing the whole system is possible. Moreover, to check the precision of the model, the results are compared with a basic single-disk model, which is prevalent in two-shaft systems.

scholarly journals Flow Characteristics of a Highly Rotating Turbine Cavity System With Discharge Hole

1999 ◽  
Author(s):  
D. J. Maeng ◽  
J. S. Lee ◽  
R. Jakoby ◽  
S. Kim ◽  
S. Wittig
Keyword(s):  
Flow Field ◽  
High Speed ◽  
Rotational Velocity ◽  
Three Dimensional ◽  
Flow Characteristics ◽  
Rotating Disk ◽  
Disk System ◽  
High Speed Rotation ◽  
Measured Flow ◽  
Cavity System

An experimental investigation is performed to analyze the flow characteristics of a turbine cavity system containing discharge holes installed in a rotating disk. The turbine cavity system is composed of a rotating disk and two stationary disks on both sides of the rotating disk. The air flow is induced into the upstream cavity, and then discharged into the downstream cavity through 8 discharge holes in the rotating disk. The flow field in each cavity at high-speed rotation of the rotor was measured by a three-dimensional LDV system. The measured flow field is analyzed to understand the flow structures, and further provide information for studying the heat transfer behaviors of the turbine disk system. The overall flow field in the upstream cavity shows a negligible axial velocity with a relatively small rotational velocity, less than 10% of the rotor speed. The downstream cavity flow has a high rotational velocity close to the rotational speed of the discharged jets, due to the direct circumferential momentum transfer from the discharged jets. The interaction between the discharged jet and the downstream stator disk induces an asymmetric development of the spreading wall jet, which results in a relative circumferential motion to the revolving discharged jet. The whole flow field in the downstream cavity is divided into several flow regions according to their features.

An Application of Torsional Wave Analysis to Turbogenerator Rotor Shaft Response

1992 ◽  
Vol 114 (2) ◽  
pp. 149-153 ◽  
Author(s):  
R. Bogacz ◽  
T. Szolc ◽  
H. Irretier
Keyword(s):  
Cross Sections ◽  
High Speed ◽  
Equations Of Motion ◽  
Wave Theory ◽  
Continuous Model ◽  
Rotor Shaft ◽  
Shaft System ◽  
Stepped Shaft ◽  
Angular Velocities ◽  
Turbogenerator Rotor

In this paper transient torsional vibrations of a steam turbogenerator rotor shaft system due to high speed reclosing of the electric network are investigated. The analysis is performed using torsional elastic wave theory applied to a continuous model in the form of a stepped shaft. Wave solutions of the equations of motion are used in order to determine dynamic torsional elastic moments and vibratory angular velocities in cross-sections of the turbine shafts. The results are illustrated in the form of graphs.

Inertia Effects in Fully Developed Axisymmetric Laminar Flow

1971 ◽  
Vol 93 (3) ◽  
pp. 408-414 ◽  
Author(s):  
E. Makay ◽  
P. R. Trumpler
Keyword(s):  
Integral Equations ◽  
High Speed ◽  
Equations Of Motion ◽  
Rotating Disk ◽  
Navier Stokes ◽  
Centrifugal Impeller ◽  
Navier Stokes Equation ◽  
Inertia Effects ◽  
Nonlinear Form ◽  
Clearance Face

The three components of the Navier-Stokes equation are solved here simultaneously in their nonlinear form for axisymmetric radial inward and outward flow cases between two parallel rotating walls. Examples of application in rotating machinery are close clearance face seals, thrust bearings, high speed thrust device, rotating disk, narrow gap between centrifugal impeller and housing, etc. The differential equations of motion with the proper boundary conditions were converted into integral equations of the “Fredholm second kind” type and solutions have been obtained for the nonlinear cases. The use of integral equations greatly enhanced the advantage of the numerical solution developed here. The results are compared to simplified solutions and to solutions considering some of the nonlinear members. The effects of the inertia forces are especially emphasized and discussed in detail. The inclusion of these terms significantly affected the velocity field in the area discussed here. It is shown here that for low inward or outward flows the centrifugal force, and for high flows the convective acceleration terms have the main controlling influence on the radical velocity component.

Design and Experimental Research on Ester Ferrofluid Seal for Stern

2009 ◽  
Vol 419-420 ◽  
pp. 209-212 ◽  
Author(s):  
En Xia Yang ◽  
He Ping Liu ◽  
Chuan Bo Yi ◽  
Yan Dong
Keyword(s):  
High Speed ◽  
Magnetic Particles ◽  
New Technology ◽  
Experimental Result ◽  
Lubricating Oil ◽  
Shaft System ◽  
Magnetization Intensity ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Pressure Resistance

A special seal is required at stern shaft, since it must serve the purposes of preventing both leakage of lubricating oil and seawater entering the stern shaft system. Improper design might cause leakage of fuel and pollution to the environment. Besides, the safety of machinery operation will also be affected. Ferrofluid seal is superior in terms of features such as long life, zero leakage, structure simplicity, fitting purposes of high-speed rotation, making it a new technology of sealing the stern shaft. In the following text, magnetic particles of Fe3O4 and solution of glyceride are made through proper chemical reactions, after which they are mixed as ferrofluid sealing liquid, and the performance of the liquid is studied experimentally. The experimental result indicates that magnetization intensity of the ferrofluid is increased as the intensity of outside magnetic field increases. Experimental instruments are designed for the purpose of research on ester magnetic fluid seal for stern. Through the experiment, performance of pressure resistance of esterified Fe3O4 ferrofliud is studied; also, main factors influencing pressure resistance of the studied ferrofliud are analyzed. The results indicate: pressure resistance decreases with increasing seal clearance or shaft rotation speed; whereby it is increased with the enhancement of saturated magnetic intensity of the ferrofliud.

scholarly journals Sound Noise Generated from Ball Bearing in High Speed Rotation

1978 ◽  
Vol 21 (158) ◽  
pp. 1306-1310 ◽  
Author(s):  
Akio NAGAMATSU ◽  
Masaho FUKUDA
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
High Speed Rotation ◽  
Speed Rotation

Analysis of the Lubrication Regimes at the Small End and Big End of a Connecting Rod of a High Performance Motorbike Engine

2012 ◽  
Author(s):  
Luca Bertocchi ◽  
Matteo Giacopini ◽  
Daniele Dini
Keyword(s):  
Rotational Speed ◽  
High Speed ◽  
High Performance ◽  
Hydrodynamic Lubrication ◽  
Vertical Axis ◽  
Connecting Rod ◽  
Lubrication Regimes ◽  
High Speed Rotation ◽  
Speed Rotation ◽  
Squeeze Effect

In the present paper, the algorithm proposed by Giacopini et. al. [1], based on a mass-conserving formulation of the Reynolds equation using the concept of complementarity is suitably extended to include the effects of compressibility, piezoviscosity and shear-thinning on the lubricant properties. This improved algorithm is employed to analyse the performance of the lubricated small end and big end bearings of a connecting rod of a high performance motorbike engine. The application of the algorithm proposed to both the small end and the big end of a con-rod is challenging because of the different causes that sustain the hydrodynamic lubrication in the two cases. In the con-rod big end, the fluid film is mainly generated by the relative high speed rotation between the rod and the crankshaft. The relative speed between the two races forms a wedge of fluid that assures appropriate lubrication and avoids undesired direct contacts. On the contrary, at the con-rod small end the relative rotational speed is low and a complete rotation between the mating surfaces does not occurs since the con-rod only oscillates around its vertical axis. Thus, at every revolution of the crankshaft, there are two different moments in which the relative rotational speed between the con-rod and the piston pin is null. Therefore, the dominant effect in the lubrication is the squeeze caused by the high loads transmitted through the piston pin. In particular both combustion forces and inertial forces contribute to the squeeze effect. This work shows how the formulation developed by the authors is capable of predicting the performance of journal bearings in the unsteady regime, where cavitation and reformation occur several times. Moreover, the effects of the pressure and the shear rate on the density and on the viscosity of the lubricant are taken into account.

Sign in / Sign up

Export Citation Format

Share Document