Effects of Flow Control on Forced Response and Performance of a Transonic Compressor

2002 ◽  
Author(s):  
S. Todd Bailie ◽  
Wing F. Ng ◽  
Alfred L. Wicks ◽  
William W. Copenhaver
Keyword(s):  
Flow Control ◽  
Rotor Blade ◽  
Forced Response ◽  
Strain Gages ◽  
Complex Flow ◽  
Compressor Blades ◽  
Transonic Compressor ◽  
Engine Order ◽  
Blade Vibrations ◽  
And Performance

The main contributor to the high-cycle fatigue of compressor blades is the response to aerodynamic forcing functions generated by an upstream row of stators or inlet guide vanes. Resonant response to engine order excitation at certain rotor speeds is especially damaging. Studies have shown that flow control by trailing edge blowing (TEB) can reduce stator wake strength and the amplitude of the downstream rotor blade vibrations generated by the unsteady stator-rotor interaction. In the present study, the effectiveness of TEB to reduce forced blade vibrations was evaluated in a modern transonic compressor rig. A row of wake generator (WG) vanes with TEB capability was installed upstream of the rotor, which was instrumented with strain gages. Data was collected with and without TEB at various rotor speeds involving resonance crossings. Using 0.8% of the compressor core flow for TEB along the full WG-span, rotor blade strain was reduced by 66% at the first torsional resonance crossing. Substantial reductions were also achieved with only partial span TEB. The results demonstrate the effectiveness of the TEB technique for reducing rotor vibrations in the complex flow environment of a closely-spaced transonic stage row. Moderate increases in stage performance were also measured.

Experimental Reduction of Transonic Fan Forced Response by IGV Flow Control

2004 ◽  
Author(s):  
S. Todd Bailie ◽  
Wing F. Ng ◽  
William W. Copenhaver
Keyword(s):  
Flow Control ◽  
Forced Response ◽  
Resonant Response ◽  
Compressor Blades ◽  
Resonant Amplitude ◽  
Engine Order ◽  
Blade Vibrations ◽  
Fan Blade ◽  
Transonic Fan ◽  
Bending Response

The main contributor to the high-cycle fatigue of compressor blades is the response to aerodynamic forcing functions generated by an upstream row of stators or inlet guide vanes. Resonant response to engine order excitation at certain rotor speeds can be especially damaging. Studies have shown that flow control by trailing edge blowing (TEB) can reduce stator wake strength and the amplitude of the downstream rotor blade vibrations generated by the unsteady stator-rotor interaction. In the present study, the effectiveness of TEB to reduce forced fan blade vibrations was evaluated in a modern single-stage transonic fan rig. Data was collected for multiple uniform full-span TEB conditions over a range of rotor speed including multiple modal resonance crossings. Resonant response sensitivity was generally characterized by a robust region of strong attenuation. The baseline resonant amplitude of the first torsion mode, which exceeded the endurance limit on the critical blade, was reduced by more than 80% with TEB at 1.0% of the total rig flow. The technique was also found to be modally robust; similar reductions were achieved for all tested modal crossings, including more than 90% reduction of the second LE bending response using 0.7% of the rig flow.

Experimental Reduction of Transonic Fan Forced Response by Inlet Guide Vane Flow Control

2009 ◽  
Vol 132 (2) ◽  
Author(s):  
S. Todd Bailie ◽  
Wing F. Ng ◽  
William W. Copenhaver
Keyword(s):  
Flow Control ◽  
Guide Vane ◽  
Leading Edge ◽  
Forced Response ◽  
Inlet Guide Vane ◽  
Resonant Response ◽  
Compressor Blades ◽  
Resonant Amplitude ◽  
Blade Vibrations ◽  
Transonic Fan

The main contributor to the high cycle fatigue of compressor blades is the response to aerodynamic forcing functions generated by an upstream row of stators or inlet guide vanes. Resonant response to engine order excitation at certain rotor speeds can be especially damaging. Studies have shown that flow control by trailing edge blowing (TEB) can reduce stator wake strength and the amplitude of the downstream rotor blade vibrations generated by the unsteady stator-rotor interaction. In the present study, the effectiveness of TEB to reduce forced fan blade vibrations was evaluated in a modern single-stage transonic fan rig. Data were collected for multiple uniform full-span TEB conditions over a range of rotor speeds including multiple modal resonance crossings. Resonant response sensitivity was generally characterized by a robust region of strong attenuation. The baseline resonant amplitude of the first torsion mode, which exceeded the endurance limit on the critical blade, was reduced by more than 80% with TEB at 1.0% of the total rig flow. The technique was also found to be modally robust; similar reductions were achieved for all tested modal crossings, including more than 90% reduction in the second leading-edge bending response using 0.7% of the rig flow.

Influence of Gap Detailing on Calculated Unsteady Non-Adjacent Blade Row Aero-Forcing in a Transonic Compressor Stage

2020 ◽  
Vol 142 (11) ◽  
Author(s):  
Tobias Gezork ◽  
Paul Petrie-Repar
Keyword(s):  
Guide Vane ◽  
Computational Cost ◽  
Life Time ◽  
Forced Response ◽  
Inlet Guide Vane ◽  
Compressor Blades ◽  
Transonic Compressor ◽  
Forcing Function ◽  
Gap Flow ◽  
Blade Row

Abstract Resonant or close to resonant forced response excitation of compressor blades limits component life time and can potentially lead to high-cycle fatigue failure if the exciting forces are large and damping is insufficient. When numerically quantifying the forcing function by means of simulations, simplifications are typically made in the analysis to reduce complexity and computational cost. In this paper, we numerically investigate how the blade forcing function is influenced by the rotor tip gap flow and by flow across gaps in the upstream variable inlet guide vane row. Unsteady simulations are made using a test rig geometry where a forcing crossing with an excitation from a non-adjacent blade row had previously been measured. The effects of the gaps on the forcing function for the first torsion mode are presented for both the non-adjacent blade row excitation (changes compared with a case without gaps indicating a 20% reduction) and an adjacent excitation (changes indicating an 80% increase in terms of forcing function amplitude comparing with a case without gaps).

3D Inverse Design Loading Strategy for Transonic Axial Compressor Blading

2003 ◽  
Author(s):  
A. J. Medd ◽  
T. Q. Dang ◽  
L. M. Larosiliere
Keyword(s):  
Rotor Blade ◽  
Axial Compressor ◽  
Design Procedure ◽  
Inverse Design ◽  
Pressure Loading ◽  
Transonic Compressor ◽  
Key Features ◽  
Transonic Axial Compressor ◽  
And Performance ◽  
Performance Results

A pressure-loading tailoring scheme for transonic axial compressor blading is developed with the goal of managing the passage shock in order to reduce loss and enhance stability. This loading distribution along with other prescribed quantities is employed in a 3-D viscous inverse design procedure to refine initial rotor blade geometries of an advanced 2-stage transonic compressor. Key features of this loading strategy are discussed in the context of their impact on flow structure and performance. Results are presented showing the merits of this scheme.

scholarly journals Determination of Serviceability Limits of a Turboshaft Engine by the Criterion of Blade Natural Frequency and Stall Margin

Aerospace ◽  
2019 ◽  
Vol 6 (12) ◽  
pp. 132 ◽  
Author(s):  
Yaroslav Dvirnyk ◽  
Dmytro Pavlenko ◽  
Radoslaw Przysowa
Keyword(s):  
Axial Compressor ◽  
Operational Experience ◽  
Two Phase ◽  
Compressor Blades ◽  
Stall Margin ◽  
Wear Process ◽  
Engine Order ◽  
Gradual Loss ◽  
And Performance ◽  
Turboshaft Engine

This paper analyzes the health and performance of the 12-stage axial compressor of the TV3-117VM/VMA turboshaft operated in a desert environment. The results of the dimensional control of 4800 worn blades are analyzed to model the wear process. Operational experience and two-phase flow simulations are used to assess the effectiveness of an inlet particle separator. Numerical modal analysis is performed to generate the Campbell diagram of the worn blades and identify resonant blade vibrations which can lead to high cycle fatigue (HCF): mode 7 engine order 30 in the first stage and mode 8 engine order 60 in the fourth. It is also shown that the gradual loss of the stall margin over time determines the serviceability limits of compressor blades. In particular, the chord wear of sixth-stage blades as high as 6.19 mm results in a reduction of the stall margin by 15–17% and a permanent stall at 770–790 flight hours. In addition, recommendations setting out go/no-go criteria are made to maintenance and repair organizations.

Non-Synchronous Aeroacoustic Interaction in an Axial Multi-Stage Compressor

2019 ◽  
Vol 141 (10) ◽  
Author(s):  
Anne-Lise Fiquet ◽  
Christoph Brandstetter ◽  
Stéphane Aubert ◽  
Mickael Philit
Keyword(s):  
Rotor Blade ◽  
High Speed ◽  
Acoustic Mode ◽  
Blade Vibration ◽  
Unsteady Pressure ◽  
Multi Stage ◽  
Engine Order ◽  
Major Interest ◽  
Blade Vibrations ◽  
Magnet Coil

Abstract Non-engine order rotor blade vibration is an aeroelastic phenomenon of major interest for compressor designers resulting from excitation of rotor blade modes through aerodynamic instabilities. Indicators for a comparable type of instability, caused by propagating acoustic modes, have been observed in an experimental multistage high-speed compressor by Safran Helicopter Engines. It is intended to understand the cause of these instabilities by combining experimental data and numerical simulations. Unsteady pressure measurements were carried out by case-mounted and stator-mounted transducers. Rotor tip-timing and magnet-coil sensor systems were installed to measure the blade vibrations. Experimental results show non-engine order signatures in the unsteady pressure signal coherent to the shifted frequency of blade vibrations. In the present paper, the waveform of these oscillations is analyzed in detail, showing a dominant propagating acoustic mode interacting with vibrations of rotor 2. The root cause for the non-synchronous oscillations is identified as an acoustic mode that is cutoff downstream of rotor 3. During the test, the mode changes its frequency and circumferential order, affecting the amplitude of associated blade vibrations.

On the Forced Response Predictions and Life Improvements of an Industrial Axial Compressor Rotor Blade

2021 ◽  
Author(s):  
Senthil Krishnababu ◽  
Giuseppe Bruni ◽  
Agnieszka Frach
Keyword(s):  
Rotor Blade ◽  
Linear Time ◽  
Axial Compressor ◽  
Response Prediction ◽  
Time Frame ◽  
Forced Response ◽  
Flow Solver ◽  
Compressor Rotor ◽  
Design Changes ◽  
Engine Order

Abstract Improvements made to the high cycle fatigue life of an industrial compressor rotor blade for tip active modes through aerodynamic design changes and aero-mechanical assessments are presented in this paper. Typical aero-mechanical computations involved utilising an in-house linear-harmonic solver to compute the aero damping. In parallel, a novel hybrid model with whole-anulus domain for the blade rows of interest followed by a single passage domain for the rest of the compressor was used to compute the modal forcing. In addition to the standard blade passing resonances, low engine order excitations due to vane number differences, were analysed. This was achieved within a time frame consistent with the product design cycle by using TurboStream, a GPU based non-linear time domain unsteady flow solver. The excitation due to low engine order resonance was found to be influenced by a harmonic of upstream blade passing frequency. When considering a design change targeting HCF life, the calculated reserve factors showed significant improvements for the tip modes of interest. The subsequent engine tests carried out with tip timing agreed closely with the predictions thus validating not only the design but also the forced response prediction process.

scholarly journals Blade Vibrations of a High Speed Compressor Blisk-Rotor: Numerical Resonance Tuning and Optical Measurements

1996 ◽  
Author(s):  
J. Frischbier ◽  
G. Schulze ◽  
M. Zielinski ◽  
G. Ziller ◽  
C. Blaha ◽  
...  
Keyword(s):  
Rotor Blade ◽  
High Speed ◽  
Mechanical Design ◽  
Optimization Technique ◽  
Optical Measurements ◽  
Vibration Measurement ◽  
Blade Vibration ◽  
Transonic Compressor ◽  
Resonance Tuning ◽  
Blade Vibrations

A major challenge during the design process of a modern low aspect ratio high speed axial compressor is to find rotor blade geometries that meet both, aerodynamic and mechanical requirements. This paper deals with the mechanical design of a transonic compressor blade. In order to meet the mechanical requirements in a short development time, new methods were used: A numerical optimization tool and an optical blade vibration measurement method: The numerical resonance tuning took advantage of a semi-automatic optimization technique, based on a Finite Element vibration anlysis tool. The intention was to find a geometry which has no critical resonances (with fundamental engine orders) within the operation range. To verify the calculated blade natural frequencies and eigen-values standard shaker tests using a laser holography system were carried out. Blades under g-load in the running compressor were investigated with an in-house developed vibration measurement system. This system is able to measure frequencies and amplitudes of the rotor blade vibrations without blade instrumentation but small optical probes, mounted in the compressor casing. The measured resonance points are in good agreement with the predictions. All amplitudes are far below the blade fatigue limits.

Effect of Maximum Camber Location on Aerodynamics Performance of Transonic Compressor Blades

2005 ◽  
Author(s):  
N. X. Chen ◽  
H. W. Zhang ◽  
H. Du ◽  
Y. J. Xu ◽  
W. G. Huang
Keyword(s):  
Rotational Velocity ◽  
Pressure Ratio ◽  
Engineering Thermophysics ◽  
Axial Fan ◽  
Complex Flow ◽  
Compressor Blades ◽  
Obvious Effect ◽  
Transonic Compressor ◽  
Academy Of Sciences ◽  
Total Pressure Ratio

It is well known that to increase rotational velocity is one of the effective measures to increase total pressure ratio. With increasing velocity, under the condition of transonic flow, the obvious effect of maximum camber location on aerodynamics performance of compressor blades especially in the supersonics zone can be found. In order to reduce the blade losses and to improve the blade design methodology it is necessary to study this complex flow mechanism. This paper describes only the influence of relative maximum camber location on aerodynamics performance, mainly adiabatic efficiency. As an example an axial fan was designed and calculated by the methodologies developed at the Institute of Engineering Thermophysics, Chinese Academy of Sciences.

Design and performance evaluation of a pump-as-turbine micro-hydro test facility with incorporated inlet flow control

2015 ◽  
Vol 78 ◽  
pp. 1-6 ◽  
Author(s):  
D.R. Giosio ◽  
A.D. Henderson ◽  
J.M. Walker ◽  
P.A. Brandner ◽  
J.E. Sargison ◽  
...  
Keyword(s):  
Performance Evaluation ◽  
Flow Control ◽  
Test Facility ◽  
Inlet Flow ◽  
And Performance
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