Blade Loss - Explore the Science & Experts | ideXlab

Scan Science and Technology

Contact Leading Edge Experts & Companies

Blade Loss

The Experts below are selected from a list of 216 Experts worldwide ranked by ideXlab platform

Alan Palazzolo – 1st expert on this subject based on the ideXlab platform

  • long duration Blade Loss simulations including thermal growths for dual rotor gas turbine engine
    Journal of Sound and Vibration, 2008
    Co-Authors: Alan Palazzolo, Andy Provenza, Charles Lawrence, Kelly S Carney

    Abstract:

    This paper presents an approach for Blade Loss simulation including thermal growth effects for a dual-rotor gas turbine engine supported on bearing and squeeze film damper. A nonlinear ball bearing model using the Hertzian formula predicts ball contact load and stress, while a simple thermal model estimates the thermal growths of bearing components during the Blade Loss event. The modal truncation augmentation method combined with a proposed staggered integration scheme is verified through simulation results as an efficient tool for analyzing a flexible dual-rotor gas turbine engine dynamics with the localized nonlinearities of the bearing and damper, with the thermal growths and with a flexible casing model. The new integration scheme with enhanced modeling capability reduces the computation time by a factor of 12, while providing a variety of solutions with acceptable accuracy for durations extending over several thermal time constants.

  • an efficient algorithm for Blade Loss simulations using a high fidelity ball bearing and damper model
    ASME 2003 International Design Engineering Technical Conferences and Computers and Information in Engineering Conference, 2003
    Co-Authors: Nikhil Kaushik, Alan Palazzolo, Andy Provenza, Charles Lawrence, Kelly S Carney

    Abstract:

    This paper presents a novel approach for Blade Loss simulation of an aircraft gas turbine rotor mounted on rolling element bearings with squeeze film dampers. The modal truncation augmentation (MTA) method provides an efficient tool for modeling this large order system with localized nonlinearities in the ball bearings. The gas turbine engine, which is composed of the power turbine and gas generator rotors, is modeled with 38 lumped masses. A nonlinear angular contact bearing model is employed, which has ball and race degrees of freedom and uses a modified Hertzian contact force between the races and balls. This combines a dry contact force and an equivalent viscous damping force. Prediction of the maximum contact load and the corresponding stress on an elliptical contact area between the races and balls is made during the Blade Loss simulations. A finite-element based squeeze film damper (SFD), which determines the pressure profile of oil film and calculates damper forces for any type of whirl orbit, is developed, verified, and utilized in the simulations. The new approach is shown to provide efficient and accurate predictions of whirl amplitudes, maximum contact load and stress in the bearings, transmissibility, the maximum and minimum damper pressures and amount of unbalance force for incipient oil film cavitation.Copyright © 2003 by ASME

  • Transient analysis of plain and tilt pad journal bearings including fluid film temperature effects
    Journal of Tribology-transactions of The Asme, 1996
    Co-Authors: R. K. Gadangi, Alan Palazzolo

    Abstract:

    The paper considers vibration response of spinning shafts supported by flexible fluid film bearings to sudden mass imbalance (Blade Loss). A time transient study of the plain journal bearing with thermal effects is performed. A comparison between three transient analyses is performed. The three transient analyses studied are, the full nonlinear analysis, linear analysis using dynamic coefficients, and pseudo transient analysis using static application of dynamic loads. The validity of the nonlinear transient analysis is checked by matching the lower unbalance results with the linear analysis and the static equilibrium position results with Newton-Raphson iterative scheme. A nonlinear transient analysis of the tilt pad journal bearing is also performed, and a comparison is drawn between the three approaches.

Jie Hong – 2nd expert on this subject based on the ideXlab platform

  • Theoretical and experimental investigation on the sudden unbalance and rub-impact in rotor system caused by Blade off
    Mechanical Systems and Signal Processing, 2016
    Co-Authors: Cun Wang, Yanhong Ma, Dayi Zhang, Zhichao Liang, Jie Hong

    Abstract:

    Abstract Blade Loss from a running turbofan rotor will introduce sudden unbalance into the dynamical system, and as a consequence leads to the rub-impact, the asymmetry of rotor and a series of interesting dynamic characteristics. The paper focuses on the theoretical study on the sudden unbalance and rub-impact caused by Blade Loss, in particular investigates the response of the rotor on a rotor test rig with sudden unbalance and rub-impact device designed respectively. The results reveal that the sudden unbalance will induce impact effect on the rotor, and critical speed frequency is excited in frequency spectrum. Meantime, the impact effect is more obvious for the rotor operating above critical speed. The influence of rub-impact is considered as additional constraint to the rotor, analyzed by the theory of time-varying system for the first time, and the results are evaluated by experimental tests. The study shows that great attention should be paid to the dynamical design for the overhung rotor system, additional constraint and corresponding analysis method in rub-impact need to be intensively studied.

  • Experimental Investigation on Dynamical Response of an Overhung Rotor due to Sudden Unbalance
    Volume 7B: Structures and Dynamics, 2015
    Co-Authors: Yanhong Ma, Dayi Zhang, Zhichao Liang, Jie Hong

    Abstract:

    Blade Loss is a typical extreme load in the turbo machinery, which can cause intense vibration in rotor and huge loads in supporting system due to the sudden unbalance applied on the disk. An overhung rotor-support system is built to study the dynamic characteristics of rotor and support experimental system under the sudden unbalance excitation. The responses due to a mass Loss are tested respectively both in subcritical state and in supercritical state, further the orbits of the rotor and load transmitting process on the stator are obtained and investigated. Moreover, the impact effect of response achieved by a mechanical model is presented to compare with the test result. The results show that sudden unbalance can induce an impact effect on the rotor system with response containing rotational speed frequency and natural frequency in frequency domain. The impact effect is more evident for flexible rotor than the rigid rotor, and the vibration response exhibits local effect. As a consequence the paper provides a reference and basis for the dynamical design and analysis for flexible overhung rotor system suffering sudden unbalance.Copyright © 2015 by ASME

  • Safety design method of fan rotor system in aeroengine due to extreme loadings
    2015 First International Conference on Reliability Systems Engineering (ICRSE), 2015
    Co-Authors: Jie Hong, Dayi Zhang, Meiling Xu, Zhichao Liang

    Abstract:

    Fan Blade Loss is the most serious condition of typical extreme working conditions in turbofan engines. The transient huge unbalance force leads to the complicated and destructive vibration response of the rotor system. The paper proposed a set of safety design method for the rotor system, which ensured the engine to stop safely after the fan Blade lost. The variable stiffness supporting structure at the rear of the fan was presented and its parameters were optimized through dynamic characteristics calculation. The results revealed that the vibration response of the rotor system could be suppressed during the speed reduction process. The spherical matching surface between the bearing ring and the rotation shaft could reduce the impact of the large shaft deformation, and enhanced the bearing’s safety.

P. Verrier – 3rd expert on this subject based on the ideXlab platform

  • A Method for Assessing the Turbine Generator Set Shaft-Line Behavior in Accidental Situations
    Proceedings of the 9th IFToMM International Conference on Rotor Dynamics, 2015
    Co-Authors: Nicolas Guilloteau, Ionel Nistor, Nabila Sellali-haraigue, Pierre Yves Couzon, P. Verrier

    Abstract:

    Ensuring the operating safety of electrical power plants is a major issue for operators. Regarding turbine generator sets, a risk was identified due to the potential Loss of one or more low pressure last stage Blades of the turbine which could lead to a large unbalance, and then to an accident. This kind of accident is generally avoided using several means among which robust design, condition monitoring and periodic non destructive inspections. Nevertheless, safety studies must be undertaken. This led researchers to develop realistic numerical methods to predict the effects of such an accident. In this framework, EDF R&D has developed its own method to describe the most accurately the dynamic behavior of a shaft-line in an accidental situation caused by a Blade Loss. The objective is to evaluate the loads on the bearings in these conditions and compare them to the maximum design loads provided by the manufacturers. This methodology is composed of two phases. The first one focuses on the study of the shaft-line behavior before the Blade Loss considering the linear behavior of the bearings oil film: a preliminary static computation is made under gravity loads considering the altimetry of the bearings. Loads on the bearings resulting of this calculation are used by a bearing code in order to compute the dynamic coefficients associated with the oil film. Then, the harmonic response to unbalance is calculated for different unbalance positions. The objective is to find the critical positions, critical rotational speeds and the most loaded bearings, for which a nonlinear modeling of the oil film is to be considered. The second phase starts at the instant which follows the Blade Loss and simulates the shutdown of the turbine. The simulation of the transient response under unbalance is performed taking into account the nonlinear behavior of the most loaded bearings oil films. The aim is to estimate the maximum loads that the bearings have to support, especially when the rotor to stator contact occurs. In this paper, the steps described above are detailed and applied on an industrial study. Results and performances are presented as well.

  • A method for assessing the turbine generator set shaft-line behavior in accidental situations
    Mechanisms and Machine Science, 2015
    Co-Authors: Nicolas Guilloteau, Ionel Nistor, Nabila Sellali-haraigue, Pierre Yves Couzon, P. Verrier

    Abstract:

    © Springer International Publishing Switzerland 2015. Ensuring the operating safety of electrical power plants is a major issue for operators. Regarding turbine generator sets, a risk was identified due to the potential Loss of one or more low pressure last stage Blades of the turbine which could lead to a large unbalance, and then to an accident. This kind of accident is generally avoided using several means among which robust design, condition monitoring and periodic non destructive inspections. Nevertheless, safety studies must be undertaken. This led researchers to develop realistic numerical methods to predict the effects of such an accident. In this framework, EDF R&D has developed its own method to describe the most accurately the dynamic behavior of a shaft-line in an accidental situation caused by a Blade Loss. The objective is to evaluate the loads on the bearings in these conditions and compare them to the maximum design loads provided by the manufacturers. This methodology is composed of two phases. The first one focuses on the study of the shaft-line behavior before the Blade Loss considering the linear behavior of the bearings oil film: a preliminary static computation is made under gravity loads considering the altimetry of the bearings. Loads on the bearings resulting of this calculation are used by a bearing code in order to compute the dynamic coefficients associated with the oil film. Then, the harmonic response to unbalance is calculated for different unbalance positions. The objective is to find the critical positions, critical rotational speeds and the most loaded bearings, for which a nonlinear modeling of the oil film is to be considered. The second phase starts at the instant which follows the Blade Loss and simulates the shutdown of the turbine. The simulation of the transient response under unbalance is performed taking into account the nonlinear behavior of the most loaded bearings oil films. The aim is to estimate the maximum loads that the bearings have to support, especially when the rotor to stator contact occurs. In this paper, the steps described above are detailed and applied on an industrial study. Results and performances are presented as well.