scholarly journals Discussion: “An Experimental and Theoretical Study of Cavitation in a Finite Submerged Squeeze Film Damper” (Ku, Chiao-Ping, and Tichy, J. A., 1990, ASME J. Tribol., 112, pp. 725–732)

1990 ◽  
Vol 112 (4) ◽  
pp. 733-733
Author(s):  
F. Zeidan
Keyword(s):  
Theoretical Study ◽  
Squeeze Film ◽  
Squeeze Film Damper

scholarly journals A Theoretical Investigation of an Overhung Flexible Rotor Mounted on Uncentralized Squeeze-Film Damper Bearings and Flexible Supports

1982 ◽  
Author(s):  
R. A. Cookson ◽  
Xin-Hai Feng
Keyword(s):  
Theoretical Study ◽  
Effective Means ◽  
Complex Model ◽  
Squeeze Film ◽  
Flexible Rotor ◽  
Squeeze Film Damper ◽  
Surrounding Structure ◽  
Turbine Disc ◽  
Flexible Supports ◽  
Selection Of

Previous investigations have shown that the uncentralized type of squeeze-film damper is an effective means of reducing the transmission of unbalance forces into the supporting structure. In this theoretical study a more complex model, which includes an overhung “fan” disc and a noncentral “turbine” disc, has been employed. This model represents the conventional gas turbine somewhat closer than does the previously studied single disc system. This investigation has shown that it is possible to minimize the force transmitted into the surrounding structure by a careful selection of squeeze-film damper characteristics, although it may be found that some larger amplitudes of motion accompany the minimized transmissibility.

Ball bearing turbocharger vibration management: application on high speed balancer

2020 ◽  
Vol 21 (6) ◽  
pp. 619
Author(s):  
Kostandin Gjika ◽  
Antoine Costeux ◽  
Gerry LaRue ◽  
John Wilson
Keyword(s):  
Dynamic Behavior ◽  
High Speed ◽  
Internal Combustion Engines ◽  
Ball Bearing ◽  
Squeeze Film ◽  
Design And Technology ◽  
Squeeze Film Damper ◽  
Damping Coefficients ◽  
Bearing Loads ◽  
Stiffness And Damping

Today's modern internal combustion engines are increasingly focused on downsizing, high fuel efficiency and low emissions, which requires appropriate design and technology of turbocharger bearing systems. Automotive turbochargers operate faster and with strong engine excitation; vibration management is becoming a challenge and manufacturers are increasingly focusing on the design of low vibration and high-performance balancing technology. This paper discusses the synchronous vibration management of the ball bearing cartridge turbocharger on high-speed balancer and it is a continuation of papers [1–3]. In a first step, the synchronous rotordynamics behavior is identified. A prediction code is developed to calculate the static and dynamic performance of “ball bearing cartridge-squeeze film damper”. The dynamic behavior of balls is modeled by a spring with stiffness calculated from Tedric Harris formulas and the damping is considered null. The squeeze film damper model is derived from the Osborne Reynolds equation for incompressible and synchronous fluid loading; the stiffness and damping coefficients are calculated assuming that the bearing is infinitely short, and the oil film pressure is modeled as a cavitated π film model. The stiffness and damping coefficients are integrated on a rotordynamics code and the bearing loads are calculated by converging with the bearing eccentricity ratio. In a second step, a finite element structural dynamics model is built for the system “turbocharger housing-high speed balancer fixture” and validated by experimental frequency response functions. In the last step, the rotating dynamic bearing loads on the squeeze film damper are coupled with transfer functions and the vibration on the housings is predicted. The vibration response under single and multi-plane unbalances correlates very well with test data from turbocharger unbalance masters. The prediction model allows a thorough understanding of ball bearing turbocharger vibration on a high speed balancer, thus optimizing the dynamic behavior of the “turbocharger-high speed balancer” structural system for better rotordynamics performance identification and selection of the appropriate balancing process at the development stage of the turbocharger.

scholarly journals Influence of Eccentricity and Angular Velocity on Force Effects on Rotor of Magnetorheological Damper

2018 ◽  
Vol 180 ◽  
pp. 02091
Author(s):  
Dominik Šedivý ◽  
Petr Ferfecki ◽  
Simona Fialová
Keyword(s):  
Magnetic Induction ◽  
Magnetorheological Damper ◽  
Squeeze Film ◽  
Fluid Viscosity ◽  
Squeeze Film Damper ◽  
Viscous Forces ◽  
Angular Velocities ◽  
Volume Method ◽  
Gap Width ◽  
Made In

This article presents the evaluation of force effects on squeeze film damper rotor. The rotor is placed eccentrically and its motion is translate-circular. The amplitude of rotor motion is smaller than its initial eccentricity. The force effects are calculated from pressure and viscous forces which were measured by using computational modeling. Damper was filled with magnetorheological fluid. Viscosity of this non-Newtonian fluid is given using Bingham rheology model. Yield stress is not constant and it is a function of magnetic induction which is described by many variables. The most important variables of magnetic induction are electric current and gap width between rotor and stator. The simulations were made in finite volume method based solver. The motion of the inner ring of squeeze film damper was carried out by dynamic mesh. Numerical solution was solved for five different initial eccentricities and angular velocities of rotor motion.

Numerical investigation of dynamic and hydrodynamic characteristics of the pad in the fluid pivot journal bearing

2021 ◽  
pp. 135065012110330
Author(s):  
Tuyen Vu Nguyen ◽  
Weiguang Li
Keyword(s):  
Computational Models ◽  
Journal Bearing ◽  
Squeeze Film ◽  
Hydrodynamic Characteristics ◽  
Hydrodynamic Properties ◽  
Squeeze Film Damper ◽  
Lubricant Oil ◽  
Oil Flow ◽  
Flow Through ◽  
Bearing System

The dynamic and hydrodynamic properties of the pad in the fluid pivot journal bearing are investigated in this paper. Preload coefficients, recess area, and size gap, which were selected as input parameters to investigate, are important parameters of fluid pivot journal bearing. The pad’s pendulum angle, lubricant oil flow through the gap, and recess pressure which characterizes the squeeze film damper were investigated with different preload coefficients, recess area, and gap sizes. The computational models were established and numerical methods were used to determine the equilibrium position of the shaft-bearing system. Since then, the pendulum angle of the pad, liquid flow, and recess pressure were determined by different eccentricities.

scholarly journals Dynamic Performance of a Squeeze Film Damper with a Cylindrical Roller Bearing under a Large Static Radial Loading Range

Machines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 14 ◽  
Author(s):  
Hans Meeus ◽  
Jakob Fiszer ◽  
Gabriël Van De Velde ◽  
Björn Verrelst ◽  
Wim Desmet ◽  
...  
Keyword(s):  
Roller Bearing ◽  
Squeeze Film ◽  
Stable Operation ◽  
Large Power ◽  
Squeeze Film Damper ◽  
Depth Analysis ◽  
Rotor Support ◽  
Cylindrical Roller Bearing ◽  
Radial Loading ◽  
Cylindrical Roller

Turbomachine rotors, supported by little damped rolling element bearings, are generally sensitive to unbalance excitation. Accordingly, most machines incorporate squeeze film damper technology to dissipate mechanical energy caused by rotor vibrations and to ensure stable operation. When developing a novel geared turbomachine able to cover a large power range, a uniform mechanical drivetrain needs to perform well over the large operational loading range. Especially, the rotor support, containing a squeeze film damper and cylindrical roller bearing in series, is of vital importance in this respect. Thus, the direct objective of this research project was to map the performance of the envisioned rotor support by estimating the damping ratio based on the simulated and measured vibration response during run-up. An academic test rig was developed to provide an in-depth analysis on the key components in a more controlled setting. Both the numerical simulation and measurement results exposed severe vibration problems for an insufficiently radial loaded bearing due to a pronounced anisotropic bearing stiffness. As a result, a split first whirl mode arose with its backward component heavily triggered by the synchronous unbalance excitation. Hence, the proposed SFD does not function properly in the lower radial loading range. Increasing the static load on the bearing or providing a modified rotor support for the lower power variants will help mitigating the vibration issues.

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