ConferenceProceedings of the ASME Turbo Expo · January 1, 2025
The second part of the two-part paper describes the impact of the improved strain energy-based model on the mistuned blade response of a non-isolated mode family. This paper concentrates on coupling aerodynamic and structural dynamics into the FMM method t ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2023
One of the grand challenges in turbomachinery forced response is accurately predicting individual blade responses in a system. This paper helps address these challenges and describes an improved FMM model for computing the mistuned forced response of an em ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2023
When an unsteady aerodynamic instability coalesces with a natural mode of vibration, Non-Synchronous Vibrations (NSV) can occur. Often in turbomachinery, vortex shedding, or tip gap flow causes frequency lock-in to the compressor or turbine blade bending o ...
Full textCite
ConferenceAIAA Science and Technology Forum and Exposition AIAA Scitech Forum 2022 · January 1, 2022
When an unsteady aerodynamic instability interacts with the natural modes of vibration of a rigid body, lies a phenomenon known as Non-Synchronous Vibrations (NSV), often referred to as Vortex-Induced Vibrations (VIV). These vibrations cause blade failure ...
Full textCite
ConferenceAIAA Science and Technology Forum and Exposition AIAA Scitech Forum 2022 · January 1, 2022
When an unsteady aerodynamic instability interacts with the natural modes of vibration of a rigid body, lies a phenomenon known as Non-Synchronous Vibrations (NSV), also known as Vortex-Induced Vibrations (VIV). These vibrations cause blade failure in jet ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2022
Starting from an oscillating cylinder, this paper navigates the shift of a Van der Pol based Reduced-Order Model from that simple case to airfoil and turbomachinery blade. The structure will be free to vibrate under the influence of a von Karman vortex str ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2022
The current papers discuss the impact of separating the upstream and downstream forcing function contributions in an embedded compressor rotor. Previously, the authors have discussed separating the influence at a torsional mode crossing, and this paper exp ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2022
This paper builds upon a two-degree-of-freedom Van der Pol oscillator based Reduced-Order Model for studying the mechanisms around Non-Synchronous Vibrations (NSV) in turbomachinery. One degree tracks the fluid motion utilizing a combination of a tradition ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2022
This paper is a continuation of previous papers by the authors that focuses on predicting the mistuned embedded rotor blade forced response. The compressor under consideration is a part of a 3.5stage rig located at Purdue University. Previously, the curren ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2022
This paper continues previous research by the current authors in a series of papers describing the impact of multi-row interaction on the forced response behavior of embedded compressor rotors. Specifically, this work dives into an aspect of the embedded r ...
Full textCite
ConferenceAIAA Scitech 2021 Forum · January 1, 2021
This paper describes the aeromechanical aspects of forced response analysis on a 3.5 stage axial compressor. Mistuning is prominent in gas turbine engines as a result of wear and tear of blades, manufacturing variations etc. In a couple of their earlier pa ...
Cite
ConferenceAIAA Scitech 2021 Forum · January 1, 2021
This paper provides a summary of an embedded rotor mistuned forced response investigation. Forced response aeromechanics is one of the grand challenge topics, which has received much attention in literature. The current paper analyzes an embedded rotor fro ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2021
This paper expands upon a multi-degree-of-freedom, Van der Pol oscillator used to model buffet and Nonsynchronous Vibrations (NSV) in turbines. Two degreesof-freedom are used, a fluid tracking variable incorporating a Van der Pol oscillator and a classic s ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2021
This paper focuses on the impact of hub labyrinth seal leakage flows on the aeromechanical behavior of an embedded compressor rotor. End wall flows are critical in determining the performance of gas turbine engine compressors, particularly the hub leakage ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2021
This paper focusses on predicting the mistuned forced response behavior of an embedded compressor rotor blade row in a 3.5 stage axial compressor. The authors in previous papers studied the multi-row influence on the forcing function for multiple operating ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2020
This paper focuses on the impact of multi-row interaction on the forced response behavior of an embedded compressor rotor at higher order modes. The authors in previous papers have discussed about the multi-row influence at the torsional mode resonant cros ...
Full textCite
ConferenceAIAA Scitech 2019 Forum · January 1, 2019
Within the framework of a linear mode (physical or theoretical/computational) the dynamic instability (flutter) of the system and the forced response of the system (due to gust excitation, for example) can be considered separately and there is no interacti ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2018
Accuracy when assessing mistuned forced response analyses is still a mayor concern. Since a full coupled analysis is still very computational expensive, several simplifications and reduced order models are carried out. The use of a reduction method, the as ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2018
This paper focuses on the rotor forced response behavior in a 3.5-stage compressor rig. The aim is to provide an accurate prediction of forced response with the less computational effort. Previous research indicates that by reducing the computation domain ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2017
This paper presents the results from a research effort on eigenvalue identification of mistuned bladed rotor systems using the Least-Squares Complex Frequency-Domain (LSCF) modal parameter estimator. The LSCF models the frequency response function (FRF) ob ...
Full textCite
ConferenceEnergy Procedia · January 1, 2017
The Inertial CO2 Extraction System (ICES) represents a novel method of capturing CO2 from flue gas. ICES makes use of the cooling effect of supersonic expansion to cool the flue gas stream, causing CO2 in the flue gas to ch ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2017
This paper is the second part of a two-part paper that presents a comprehensive study of the higher-order mode mistuned forced response of an embedded rotor blisk in a multi-stage axial research compressor. The resonant response of the second-stage rotor ( ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2017
This paper is the first part of a two-part paper that presents a comprehensive study of the higher-order mode mistuned forced response of an embedded rotor blisk in a multistage axial research compressor. The resonant response of the second-stage rotor (R2 ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2017
This paper investigates superposition and decomposition methods when determining the forcing function on an embedded rotor in a multistage axial compressor. Under investigation is a 3-row stator/rotor/stator configuration where two stators, having the same ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2017
This paper studies a subsonic compressor case with concurrent forced response and flutter by using the Harmonic Balance method, and was inspired by historical experimental data. Forced response was observed when the rotating speed was approaching a crossin ...
Full textCite
Conference12th European Conference on Turbomachinery Fluid Dynamics and Thermodynamics, ETC 2017 · January 1, 2017
This paper aims to investigate the influence of tip clearance on aerodynamic damping maps of an oscillating low pressure turbine (LPT) unshrouded blade row. Full-scale time-marching RANS CFD simulations in ANSYS CFX® v.16.2 employing models with 0%, 1%, 2% ...
Cite
ConferenceEuropean Conference on Turbomachinery Fluid Dynamics and Thermodynamics etc · January 1, 2017
This paper aims to investigate the influence of tip clearance on aerodynamic damping maps of an oscillating low pressure turbine (LPT) unshrouded blade row. Full-scale time-marching RANS CFD simulations in ANSYS CFX® v.16.2 employing models with 0%, 1%, 2% ...
Cite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2016
Modern design principles are pushing for lighter aircraft engines and higher tip Mach numbers in steam turbines. Consequently the loading and shock structures seen on aft stages o low-pressure turbines are evolving at a fast pace. Since flutte is a high ri ...
Full textCite
Conference56th AIAA ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2015
Aeroelastic utter is a major concern of turbomachinery engineers. As such, this poten- tially catastrophic self-excitation mechanism has been the focus of many research endeavors. While most investigations have concentrated on identifying key correlations ...
Cite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2015
The effects of blade count ratio (BCR) on both the steady and unsteady blade loading and the sensitivity of generalized force to a change in mode shape (mode excitability) are studied numerically on two 2D configurations: a subsonic research compressor sta ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2015
The frequency mistuning that occurs due to manufacturing variations and wear and tear of the blades can have a significant effect on the flutter and forced response behavior of a blade row. Similarly, asymmetries in the aerodynamic or excitation forces can ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2015
For an experimental study of aerodynamic damping in an axial low pressure turbine, a single stage subsonic turbine blisk is designed and aerodynamically and aeromechanically assessed. The design goals are a low aerodynamic damping, to allow a long ring dow ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2015
The three major aeroelastic issues in the turbomachinery blades of jet engines and power turbines are forced response, non-synchronous vibrations, and flutter. Flutter primarily affects high-aspect ratio blades found in the fan, fore high-pressure compress ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2014
Vortex-induced vibration is a fluid instability present in many areas, including offshore platforms, wind turbines, and turbomachinery. The vortices due to secondary flows exert an periodic unsteady force on the elastic structure, leading to potentially da ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2014
The paper develops a reduced-order model of nonsynchronous vibration (NSV) using proper orthogonal decomposition (POD) methods. The approach was successfully developed and implemented, requiring between two and six POD modes to accurately predict CFD solut ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2014
Successful, efficient turbine design requires a thorough understanding of the underlying physical phenomena. This paper investigates the flutter phenomenon of low pressure turbine (LPT) blades seen in aircraft engines and power turbines. CFD analysis will ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2013
This paper demonstrates the potential of using a multidegree- of-freedom, traditional van der Pol oscillator to model non-synchronous vibration (NSV) in turbomachinery. It is shown that the two main characteristics of NSV are captured by the reduced-order, ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2012
This paper demonstrates the potential of using a multidegree- of-freedom, traditional van der Pol oscillator to model Non-Synchronous Vibration (NSV) in turbomachinery. It is shown that the two main characteristics of NSV are captured by the reduced-order, ...
Full textCite
Conference46th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 2010
The effect of aerodynamic asymmetries on forced response characteristics of cascades is investigated. Specifically, the present method is used to study the effect of leading edge blending in loaded rotors. The unsteady aerodynamic response of the blades to ...
Full textCite
Conference47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition · January 1, 2009
The vortex lock-in effect has been well-studied for an oscillating cylinder and numerous experimental and computational data are available. However, only recently has this phenomenon been observed for two-dimensional isolated airfoils as well as turbine ca ...
Full textCite
Conference47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition · January 1, 2009
A harmonic balance technique for the analysis of nonlinear forced response phenomenon in a two-row transonic compressor is presented. Using the present approach, each blade row is modeled using a computational grid spanning a single blade passage regardles ...
Full textCite
Conference47th AIAA Aerospace Sciences Meeting Including the New Horizons Forum and Aerospace Exposition · January 1, 2009
In this paper, the effect of aerodynamic asymmetries on the flutter characteristics of turbomachinery blades is investigated. Specifically, the present method is used to study the effect of leading edge blending in loaded and unloaded rotors. The unsteady ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · December 1, 2008
This paper presents the results of a new enforced motion method using harmonic balance computational fluid dynamics (CFD) analysis to design for NSV. Currently, most researchers employ a time domain CFD technique to directly find the frequency of the under ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · December 1, 2008
Most of the existing mistuning research assumes that the aerodynamic forces on each of the blades are identical except for an interblade phase angle shift. In reality, blades also undergo asymmetric steady and unsteady aerodynamic forces due to manufacturi ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · December 1, 2008
A nonlinear harmonic balance technique for the analysis of aerodynamic asymmetry of unsteady flows in turboma-chinery is presented. The present method uses a mixed time-domain/frequency-domain approach that allows one to compute the unsteady aerodynamic re ...
Full textCite
ConferenceIcas Secretariat 26th Congress of International Council of the Aeronautical Sciences 2008 Icas 2008 · December 1, 2008
The state of reduced order modeling of unsteady aerodynamic flows for the efficient calculation of fluid-structure interaction (aeroelasticity) is discussed as well as very recent work on olecular dynamics simulations. Starting with either a time domain or ...
Cite
ConferenceProceedings of the ASME Turbo Expo · January 1, 2007
Nearly all turbomachinery aeroelastic analyses assume that the blades are "tuned" aerodynamically. That is, all blades experience identical steady and unsteady loads (except for an interblade phase shift). This paper presents the results of a perturbations ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo · 2006
This paper presents the results of a probabilistic flutter study of a mistuned bladed disk using a high fidelity model including both structural and aerodynamic coupling. The approach used in this paper is relatively fast because it does not require any ad ...
Cite
ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 2006
In recent years, new aeromechanical problems have been encountered in turbomachinery. In particular, non-synchronous vibrations (NSV) in blades have been observed by engine companies and occur as a result of flow instabilities. As a first step towards bett ...
Full textCite
Conference12th International Congress on Sound and Vibration 2005 Icsv 2005 · December 1, 2005
The state of reduced order modeling of unsteady aerodynamic flows for the efficient calculation of fluid-structure interaction (aeroelasticity) is discussed. Reduced order modeling is a set of conceptually novel and computationally efficient techniques for ...
Cite
Conference43rd AIAA Aerospace Sciences Meeting and Exhibit Meeting Papers · January 1, 2005
Two distinctly different reduced-order models are formulated for fully nonlinear aeroelastic systems. The first is based on Proper Orthogonal Decomposition (POD). The velocity field is decomposed into a finite number of orthonormal modes, effecting order r ...
Full textCite
Conference43rd AIAA Aerospace Sciences Meeting and Exhibit Meeting Papers · January 1, 2005
In this paper, we review some recent developments for computing unsteady aerodynamic loads associated with turbomachinery aeromechanics. In particular, we example the use of frequency domain techniques for computing unsteady flows in turbomachinery. The fr ...
Full textCite
ConferenceProceedings of the ASME Turbo Expo 2004 · January 1, 2004
This paper presents the initial results from a research effort on blisk and bladed disk mistuning including both structural and aerodynamic coupling. The structural coupling model is based on the Fundamental Mistuning Model (FMM, developed by Feiner & Grif ...
Full textCite
ConferenceAmerican Society of Mechanical Engineers International Gas Turbine Institute Turbo Expo Publication IGTI · December 1, 2003
A current preliminary design method for flutter of low pressure turbine blades and vanes only requires knowledge of the reduced frequency and mode shape (real). However, many low pressure turbine (LPT) blade designs include a tip shroud, that mechanically ...
Full textCite
ConferenceAmerican Society of Mechanical Engineers International Gas Turbine Institute Turbo Expo Publication IGTI · December 1, 2003
The paper presents a method to investigate the flutter appearance in a cascade, where blades are connected together in a number of identical sectors. The key parameters of the method are vibration amplitudes and mode shapes of the blades belonging to the s ...
Full textCite
ConferenceAmerican Society of Mechanical Engineers, International Gas Turbine Institute, Turbo Expo (Publication) IGTI · 2003
In this paper, we investigate non-synchronous vibrations (NSV) in turbomachinery, an aeromechanic phenomenon in which rotor blades are driven by a fluid dynamic instability. Unlike flutter, a self-excited vibration in which vibrating rotor blades and the r ...
Cite
Conference39th Aerospace Sciences Meeting and Exhibit · December 1, 2001
The lecture addresses unsteady flow prediction from the perspective of the aeroelastic blade designer with emphasis on flutter and resonant response. The subjects discussed are the aeroelastic design problem, current state of technology, and future needs. ...
Cite
ConferenceAmerican Society of Mechanical Engineers Paper · January 1, 1998
A design approach to avoid flutter of low pressure turbine blades in aircraft engines is described. A linearized Euler analysis, previously validated using experimental data, is used for a series of parameter studies. The influence of mode shape and reduce ...
Cite
Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
The High Stability Engine Control (HISTEC) Program, managed and funded by the NASA Lewis Research Center, is a cooperative effort between NASA and Pratt & Whitney (P&W). The program objective is to develop and flight demonstrate an advanced highstability i ...
Full textCite
Conference34th AIAA ASME SAE ASEE Joint Propulsion Conference and Exhibit · January 1, 1998
This paper describes a passive damping program for fan and compressor blisks. Specific goals include the design, manufacture and spin test of two passive damping systems to achieve effective magnification factors (Q) of 50 or less for the targeted modes of ...
Cite
ConferenceProceedings of the ASME Turbo Expo · January 1, 1998
A design approach to avoid flutter of low pressure turbine blades in aircraft engines is described. A linearized Euler analysis, previously validated using experimental data, is used for a series of parameter studies. The influence of mode shape and reduce ...
Full textCite
ConferenceASME 1996 International Gas Turbine and Aeroengine Congress and Exhibition Gt 1996 · January 1, 1996
Wave rotors have been investigated over several decades in part due to their potential for increasing the maximum cycle temperature in gas turbine engines via their self-cooling mechanism. Recent activities in this field have centered on the experiments an ...
Full textCite
ConferenceAmerican Society of Mechanical Engineers Paper · January 1, 1996
Wave rotors have been investigated over several decades in part due to their potential for increasing the maximum cycle temperature in gas turbine engines via their self-cooling mechanism. Recent activities in this field have centered on the experiments an ...
Cite
ConferenceASME 1992 International Gas Turbine and Aeroengine Congress and Exposition Gt 1992 · January 1, 1992
A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes, and/or pressure disturbances from adjacent blade rows. The standard method ...
Full textCite
ConferenceASME 1992 International Gas Turbine and Aeroengine Congress and Exposition Gt 1992 · January 1, 1992
A frequent cause of turbomachinery blade failure is excessive resonant response. The most common excitation source is the nonuniform flow field generated by inlet distortion, wakes, and/or pressure disturbances from adjacent blade rows. The standard method ...
Full textCite
ConferenceAmerican Society of Mechanical Engineers Paper · January 1, 1988
An application of a simple aeroelastic model to an advanced supersonic axial flow fan is presented. Lane's cascade theory is used to determine the unsteady aerodynamic loads. Parametric studies are performed to determine the effects of mode coupling, Mach ...
Cite
ConferenceAmerican Society of Mechanical Engineers Design Engineering Division Publication DE · December 1, 1987
A procedure is outlined for determining the optimal design of friction dampers for high speed turbo-machinery blading. The procedure includes: an integration of bench test results with finite element analysis and a single mode blade model to ensure accurac ...
Cite
ConferenceProceedings of the ASME Turbo Expo · January 1, 1986
Tnis paper uses a typical section model to analytically investigate the effect of mass balancing as applied to hollow, supersonic fan blades. A procedure to determine the best configuration of an internal balancing mass to provide flutter alleviation is de ...
Full textCite
ConferenceAmerican Society of Mechanical Engineers Paper · January 1, 1985
The renewed interest in propeller propulsion is based on large reductions expected in fuel burned and direct operating costs compared to advance turbofan propulsion. Current predictions indicate that a prop-fan (Advanced Propeller) powered 120-passenger ai ...
Cite
ConferenceAmerican Society of Mechanical Engineers Paper · January 1, 1985
A discussion is presented on the stabilizing effects of dry friction on torsional blade flutter. A lumped parameter model with single degree of freedom per blade has been used to represent the rotor stage. The well-known cascade theories for incompressible ...
Cite
ConferenceAmerican Society of Mechanical Engineers Paper · December 1, 1984
The effect of pretwist and warping on the torsional vibration of short-aspect-ratio rotating beams is examined for application to the modeling of turbofan, turboprop, and compressor blades. The equations of motion and the associated boundary conditions by ...
Cite
ConferenceAIAA Journal · January 1, 1982
This paper presents an investigation of the effects of blade mistiming on the aeroelastic stability and response of a cascade in incompressible flow. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade ...
Full textCite
ConferenceCollection of Technical Papers AIAA ASME ASCE AHS ASC Structures Structural Dynamics and Materials Conference · January 1, 1981
This paper presents an investigation of the effects of blade mistuning on the aeroelastic stability and response of a cascade in incompressible flow. The aerodynamic, inertial, and structural coupling between the bending and torsional motions of each blade ...
Cite
ConferenceAmerican Society of Mechanical Engineers Paper · January 1, 1981
An investigation of the effects of mistuning on flutter and forced response of a cascade in subsonic and supersonic flows is presented. The aerodynamic and structural coupling between the bending and torsional motions and the aerodynamic coupling between t ...
Cite
