Published 2002 by National Aeronautics and Space Administration, Glenn Research Center, Available from NASA Center for Aerospace Information, National Technical Information Service [distributor in [Cleveland, Ohio], Hanover, MD, Springfield, VA .
Written in EnglishRead online
|Statement||J. Lepicovsky ... [et al.].|
|Series||NASA/TM -- 2002-211894., NASA technical memorandum -- 211894.|
|Contributions||Lepicovsky, J., NASA Glenn Research Center.|
|The Physical Object|
Download Methodology of blade unsteady pressure measurement in the NASA transonic flutter cascade
In this report the methodology adopted to measure unsteady pressures on blade surfaces in the NASA Transonic Flutter Cascade under conditions of simulated blade flutter is described.
Methodology of Blade Unsteady Pressure Measurement in the NASA Transonic Flutter Cascade In this report the methodology adopted to measure unsteady pressures on blade surfaces in the NASA Transonic Flutter Cascade under conditions of simulated blade flutter is described.
The previous work done in this cascade reported that the oscillating cascade produced waves, which for some. Methodology of blade unsteady pressure measurement in the nasa transonic flutter cascade (OCoLC) Microfiche version: Methodology of blade unsteady pressure measurement in the NASA transonic flutter cascade (OCoLC) Material Type: Document, Government publication, National government publication, Internet resource: Document Type.
An extensive set of unsteady pressure data was acquired along the midspan of a modern transonic fan blade for simulated flutter conditions. The data set was acquired in a nine-blade linear cascade with an oscillating middle blade to provide a database for the influence coefficient method to calculate instantaneous blade loadings.
the measure pressure signal. The problem of acceleration effects will be discussed later. Fig. 1 Test section of the NASA Transonic Flutter Cascade. Fig. 4 Instrumented blade KSx +x +X NASA/CR— 2. Investigations of unsteady pressure loadings on the blades of fans operating near the stall flutter boundary are carried out under simulated conditions in the NASA Transonic Flutter Cascade facility (TFC).
It has been observed that for inlet Mach numbers of aboutthe cascade flowfield exhibits intense low-frequency pressure oscillations. A parallel multiblock Navier-Stokes solver with the k ‐ ω turbulence model is used to solve the unsteady flow through an annular turbine cascade, the transonic Standard Test Case 4, Test Computations are performed on a two- and three-dimensional model of the blade row with either the Euler or the Navier-Stokes flow models.
Methodology of Blade Unsteady Pressure Measurement in the NASA Transonic Flutter Cascade,” NASA Glenn Research Center, Cleveland, OH, Report No.
NASA/TM Flush-mounted dynamic pressure transducers were installed on the center airfoil of a transonic oscillating cascade to measure the unsteady aerodynamic response. An illustration of an open book. Books. An illustration of two cells of a film strip.
Video An illustration of an audio speaker. Full text of "Unsteady Aerodynamic Response of a Linear Cascade. Kobayashi, H.: Unsteady Aerodynamic Characteristics of Annular Cascade Oscillating in Transonic Flow (3rd Report, Low Back-Pressure Supersonic Compressor Blade Flutter), Trans.
JSME, Series B, (), – (in Japanese). Google Scholar. The flutter characteristics in terms of energy transfer from the fluid to the blade and shock dynamics have been mapped out over a range of blade oscillation frequencies and static pressure ratios (SPRs) across the cascade, the latter being important as they decide the mean location of the passage shocks.
Here the application of an Euler method already leads to acceptable results for unsteady pressure and damping coefficients and hence this cascade is very appropriate for a first validation of any Navier-Stokes code. The second test case is a highly-loaded gas turbine cascade operating in transonic flow at design and off-design conditions.
Resonance Effects in the NASA Transonic Flutter Cascade Facility Investigations of unsteady pressure loadings on the blades of fans operating near the stall flutter boundary are carried out under simulated conditions in the NASA Transonic Flutter Cascade facility (TFC).
It has been observed that for inlet Mach numbers of aboutthe cascade flowfield exhibits intense low-frequency pressure. Buffum D H and Fleeter S Unsteady flow in cascades: flutter and forced response Advanced Methods for Cascade Testing, Agardograph Chivers J W H The development and application of miniature silicon pressure transducers for gas turbine engine research and development Measurement Techniques (Brussels: VKI).
Summary. This paper presents the design of a cascade and the experimental method to investigate shock inducted flutter. To examine the interaction between a shock wave and blade oscillation at transonic flow, a cascade with 7 blades, each of them separately elastically mounted, has been developed so that only an aerodynamic coupling can occur in the system.
NASA Transonic Flutter Cascade Facility The NASA GRC Transonic Flutter Cascade (TFC) is dedicated to studying the unsteady aerodynamics of oscillating airfoils, and is used to provide data for modeling the aerodynamics of blade stall flutter.
The facility combines a linear cascade wind tunnel with a high-speed drive system that imparts pitching. Transonic cascade wind tunnel. An analysis target for this study is a transonic cascade wind tunnel in the University of Tokyo.
This wind tunnel is designed for aeroelastic investigations of fan or compressor cascade, and it had been used for fundamental researches on the unsteady aerodynamic force characterist 17 and active suppression of cascade flutter The method was revealed to change the unsteady aerodynamic force acted on the blade from exciting to damping force if the phase of trailing edge oscillation was properly selected.
The suppressing effect of the control method came from its effect on passage shock movement, which was confirmed by developed flow-structure coupled method. Blade flutter of modern gas-turbine engines is one of the main issues that engine designers have to face. The most used numerical method that is employed for flutter prediction is the energy method.
the unsteady ﬂow through an annular turbine cascade, the transonic Standard Test Case 4, Test Computations are performed on a two- and three-dimensional model of the blade row with either the Euler or the Navier-Stokes ﬂow models.
Results are compared to the experimental measurements. Comparisons of the unsteady surface pressure and the. Unsteady transonic flow over cascade blades.
Validation of Three-Dimensional Euler Methods for Vibrating Cascade Aerodynamics. 1 October | Journal of Turbomachinery, Vol.No. Finite element calculations of transonic flutter in cascades. CHINGTENG HSIAO and. Inviscid-viscous coupled solution for unsteady flows through vibrating blades, part 1.
description of the method; part 2. computational results. Papers GT and GT, ASME Intl Gas Turbine and Aeroengine Congress and Expo., 1. Introduction. Flutter, a self-excited aeroelastic instability phenomenon, is a great challenge for turbomachinery design.
It could lead to eventual blade failures because of the unsteady pressure acting on the blade surface, which does work on the blade structure and adds energy to the blade.
Effects of Transducer Installation on Unsteady Pressure Measurements on Oscillating Blades Unsteady pressures were measured above the suction side of a blade that was oscillated to simulate blade stall flutter. Measurements were made at blade oscillation frequencies up to Hz.
Two types of miniature pressure transducers were used: surface. The transonic flutter cascade facility at NASA Glenn Research Cen-ter is one of a very few test facilities dedicated to unsteady aerodynam-ics of oscillating airfoils.
The facility combines a transonic linear cascade wind tunnel with a high-speed drive system. The drive system imparts torsional oscillations to the blades at prescribed interblade. Methodology of blade unsteady pressure measurement in the NASA transonic flutter cascade / by: Lepicovsky, Jan, Published: () An experimental study of tip shape effects on the flutter of aft-swept, flat-plate wings by: Dansberry, Bryan E.
Published: (). The transonic flutter cascade facility at NASA Glenn Research Center was redesigned based on a combined program of experimental measurements and numerical analyses.
The objectives of the redesign were to improve the periodicity of the cascade in steady operation, and to better quantify the inlet and exit flow conditions needed for CFD predictions. This paper describes a portion of a research effort to eliminate occurrences of flutter of low pressure turbine blades in aircraft engines.
Fundamental unsteady aerodynamic experiments in an annular cascade plus correlating analyses are conducted to improve the understanding of the flutter mechanism in these blades and to identify the key.
An illustration of an open book. Books. An illustration of two cells of a film strip. Video. An illustration of an audio speaker. Audio An illustration of a " floppy disk. Full text of "Development of a linear aerodynamic analysis for unsteady transonic cascades" See other formats.
transonic fan geometry. The transonic fan analyzed, showed flutter at part speed. The TURBO-AE code is applied to calculate the flutter observed in the wind tunnel and to understand the fl ow features that caused the instability.
Modem fa n blades, by virtue of having a small thickness. static pressure distribution is compared with the experimen-tal data in Fig. A very good agreement is achieved.
3D Cascade Geometry, Meshing and Boundary Conditions The test section of the NASA transonic ﬂutter cascade facil-ity is shown in Fig. The test section has a rectangularcross section of cm wide (pitch van. High asynchronous self-excited blade response was observed in a transonic first stage rotor during the evaluation of flutter stability in high forward speed conditions.
This candidate baseline rotor stage is a highly loaded, snubber-less bladed-disc configuration mounted in an axial low pressure compressor with tip speed in the order of m/s.
 Whitehead D. S., “ Torsional Flutter of Unstalled Cascade Blades at Zero Deflection,” Aeronautical Research Council R&MGreat Britain, Google Scholar  Carta F. O., “ Unsteady Normal Force on an Airfoil in a Periodically Stalled Inlet Flow,” Journal of Aircraft, Vol. 4, No.
5,pp. – Transonic Rotor Blade Pressure Measurement Using Fluorescent Paints. On Flowfield Periodicity in the NASA Transonic Flutter Cascade. 1 February | Journal of Turbomachinery, Vol.No. Unsteady Blade-Row Flow Calculations Using a Low-Reynolds-Number Turbulence Model.
The work described in this paper is part of a comprehensive research effort aimed at eliminating the occurrence of low pressure turbine blade flutter in aircraft engines. The results of fundamental unsteady aerodynamic experiments conducted in an annular cascade are studied in order to improve the overall understanding of the flutter mechanism.
This paper describes a finite-difference method for unsteady transonic flow computation in frequency domain and transonic flutter prediction of complete aircraft configurations. The unsteady TSD equation as well as the boundary conditions are split into the in-phase and out-of-phase components in fr.
This indicates that the present method is able to ac- curately predict unsteady pressure around oscillating blades. Fan flutter analysis Rotor 67 is a popular test case for 3D viscous flow calculations.
It is designed with 22 blades with rota- tional speed of 16 r/min at design point. The total pressure ratio is at the peak. flutter --flutter boundaries for pairs of low pressure turbine blades --influence of a vibration amplitude distribution on the aerodynamic stability of a low-pressure turbine sectored vane --a method to assess flutter stability of complex modes --flutter design of lowpressure turbine blades with cyclic symmetric modes --experimental and.
In this paper, the stall and choke flutter analyses of NACA unstaggered cascades in transonic viscous flows are presented by using a time domain approach. For the present time domain approach, a solution-adaptive finite volume method with rigid-deformable dynamic mesh treatment is adopted to solve the two-dimensional unsteady Navier-Stokes.
Flutter Analysis of a Transonic Steam Turbine Blade frequency domain solvers in combination with the energy method, which is widely used for the results obtained with the ﬂow solver LUFT  is shown for the blade pressure at 50% and 90% height in Figure4. The TRACE results show a stronger leading edge suction peak and subsequent shock.The Transonic Flutter Cascade Facility at the NASA Glenn Research Center was developed to experimentally study the details of flow mechanisms associated with fan flutter.
The cascade airfoils are instrumented to measure high-frequency unsteady flow variations in addition to the steady flow data normally recorded in cascade tests.investigate the nonlinear, unsteady aerodynamics and active flutter suppression of wings in transonic flow.
Under the initial wind tunnel test program, a NACA airfoil rectangular wing, equipped with pressure transducers, active trailing edge control surface, and two spoilers were constructed for active flutter suppression tests.