FSI-based forced response analyses of a mistuned high pressure compressor blisk

Recent numerical developments dedicated to the simulation of rotor/stator interaction involving direct structural contacts have been integrated within the Snecma industrial environment. This paper presents the first attempt to benefit from these developments and account for structural blade/casing contacts at the design stage of a high-pressure compressor blade. The blade of interest underwent structural divergence after blade/abradable coating contact occurrences on a rig test. The design improvements were carried out in several steps with significant modifications of the blade stacking law while maintaining aerodynamic performance of the original blade design. After a brief presentation of the proposed design strategy, basic concepts associated with the design variations are recalled. The iterated profiles are then numerically investigated and compared with respect to key structural criteria such as: (1) their mass, (2) the residual stresses stemming from centrifugal stiffening, (3) the vibratory level under aerodynamic forced response and (4) the vibratory levels when unilateral contact occurs. Significant improvements of the final blade design are found: the need for an early integration of nonlinear structural interactions criteria in the design stage of modern aircraft engines components is highlighted.

Download Full-text

Redesign of a High-Pressure Compressor Blade Accounting for Nonlinear Structural Interactions

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4028263 ◽

2014 ◽

Vol 137 (2) ◽

Cited By ~ 7

Author(s):

Alain Batailly ◽

Mathias Legrand ◽

Antoine Millecamps ◽

Sébastien Cochon ◽

François Garcin

Keyword(s):

High Pressure ◽

Forced Response ◽

Compressor Blade ◽

Design Stage ◽

Blade Design ◽

Early Integration ◽

Nonlinear Structural ◽

High Pressure Compressor ◽

Structural Interactions ◽

Pressure Compressor

Recent numerical developments dedicated to the simulation of rotor/stator interaction involving direct structural contacts have been integrated within the Snecma industrial environment. This paper presents the first attempt to benefit from these developments and account for structural blade/casing contacts at the design stage of a high-pressure compressor blade. The blade of interest underwent structural divergence after blade/abradable coating contact occurrences on a rig test. The design improvements were carried out in several steps with significant modifications of the blade stacking law while maintaining aerodynamic performance of the original blade design. After a brief presentation of the proposed design strategy, basic concepts associated with the design variations are recalled. The iterated profiles are then numerically investigated and compared with respect to key structural criteria such as: (1) their mass, (2) the residual stresses stemming from centrifugal stiffening, (3) the vibratory level under aerodynamic forced response, and (4) the vibratory levels when unilateral contact occurs. Significant improvements of the final blade design are found: the need for an early integration of nonlinear structural interactions criteria in the design stage of modern aircraft engines components is highlighted.

Download Full-text

Aeroelastic assessment of a highly loaded high pressure compressor exposed to pressure gain combustion disturbances

Journal of the Global Power and Propulsion Society ◽

10.22261/jgpps.f72ouu ◽

2018 ◽

Vol 2 ◽

pp. F72OUU

Author(s):

Victor Bicalho Civinelli de Almeida ◽

Dieter Peitsch

Keyword(s):

High Pressure ◽

Gas Turbines ◽

Forced Response ◽

Thermodynamic Efficiency ◽

Efficiency Gain ◽

Aerodynamic Damping ◽

High Pressure Compressor ◽

Pressure Gain Combustion ◽

Pressure Compressor ◽

Highly Loaded

A numerical aeroelastic assessment of a highly loaded high pressure compressor exposed to flow disturbances is presented in this paper. The disturbances originate from novel, inherently unsteady, pressure gain combustion processes, such as pulse detonation, shockless explosion, wave rotor or piston topping composite cycles. All these arrangements promise to reduce substantially the specific fuel consumption of present-day aeronautical engines and stationary gas turbines. However, their unsteady behavior must be further investigated to ensure the thermodynamic efficiency gain is not hindered by stage performance losses. Furthermore, blade excessive vibration (leading to high cycle fatigue) must be avoided, especially under the additional excitations frequencies from waves traveling upstream of the combustor. Two main numerical analyses are presented, contrasting undisturbed with disturbed operation of a typical industrial core compressor. The first part of the paper evaluates performance parameters for a representative blisk stage with high-accuracy 3D unsteady Reynolds-averaged Navier-Stokes computations. Isentropic efficiency as well as pressure and temperature unsteady damping are determined for a broad range of disturbances. The nonlinear harmonic balance method is used to determine the aerodynamic damping. The second part provides the aeroelastic harmonic forced response of the rotor blades, with aerodynamic damping and forcing obtained from the unsteady calculations in the first part. The influence of blade mode shapes, nodal diameters and forcing frequency matching is also examined.

Download Full-text

Model update and validation of a mistuned high-pressure compressor blisk

The Aeronautical Journal ◽

10.1017/aer.2018.149 ◽

2019 ◽

Vol 123 (1260) ◽

pp. 230-247 ◽

Cited By ~ 1

Author(s):

B. Beirow ◽

A. Kühhorn ◽

F. Figaschewsky ◽

P. Hönisch ◽

T. Giersch ◽

...

Keyword(s):

High Pressure ◽

Ambient Pressure ◽

Pressure Gauge ◽

Structural Models ◽

Forced Response ◽

Test Program ◽

Maximum Information ◽

High Pressure Compressor ◽

The Impact ◽

Pressure Compressor

ABSTRACTIn order to prepare an advanced 4-stage high-pressure compressor rig test campaign, details regarding both accomplishment and analysis of preliminary experiments are provided in this paper. The superior objective of the research project is to contribute to a reliable but simultaneously less conservative design of future high pressure blade integrated disks (blisk). It is planned to achieve trend-setting advances based on a close combination of both numerical and experimental analyses. The analyses are focused on the second rotor of this research compressor, which is the only one being manufactured as blisk. The comprehensive test program is addressing both surge and forced response analyses e.g. caused by low engine order excitation. Among others the interaction of aeroelastics and blade mistuning is demanding attention in this regard. That is why structural models are needed, allowing for an accurate forced response prediction close to reality. Furthermore, these models are required to support the assessment of blade tip timing (BTT) data gathered in the rig tests and strain gauge (s/g) data as well. To gain the maximum information regarding the correlation between BTT data, s/g-data and pressure gauge data, every blade of the second stage rotor (28 blades) is applied with s/g. However, it is well known that s/g on blades can contribute additional mistuning that had to be considered upon updating structural models.Due to the relevance of mistuning, efforts are made for its accurate experimental determination. Blade-by-blade impact tests according to a patented approach are used for this purpose. From the research point of view, it is most interesting to determine both the effect s/g-instrumentation and assembling the compressor stages on blade frequency mistuning. That is why experimental mistuning tests carried out immediately after manufacturing the blisk are repeated twice, namely, after s/g instrumentation and after assembling. To complete the pre-test program, the pure mechanical damping and modal damping ratios dependent on the ambient pressure are experimentally determined inside a pressure vessel. Subsequently the mistuning data gained before is used for updating subset of nominal system mode (SNM) models. Aerodynamic influence coefficients (AICs) are implemented to take aeroelastic interaction into account for forced response analyses. Within a comparison of different models, it is shown for the fundamental flap mode (1F) that the s/g instrumentation significantly affects the forced response, whereas the impact of assembling the compressor plays a minor role.

Download Full-text

Consequences of Borescope Blending Repairs on Modern High Pressure Compressor Blisk Aeroelasticity

Journal of Turbomachinery ◽

10.1115/1.4041672 ◽

2019 ◽

Vol 141 (2) ◽

Author(s):

Benjamin Hanschke ◽

Arnold Kühhorn ◽

Sven Schrape ◽

Thomas Giersch

Keyword(s):

High Pressure ◽

Aerodynamic Force ◽

Pressure Ratio ◽

Forced Response ◽

Response Analysis ◽

Influence Coefficient ◽

Blade Vibration ◽

Aerodynamic Damping ◽

High Pressure Compressor ◽

Pressure Compressor

Objective of this paper is to analyze the consequences of borescope blending repairs on the aeroelastic behavior of a modern high pressure compressor (HPC) blisk. To investigate the blending consequences in terms of aerodynamic damping and forcing changes, a generic blending of a rotor blade is modeled. Steady-state flow parameters like total pressure ratio, polytropic efficiency, and the loss coefficient are compared. Furthermore, aerodynamic damping is computed utilizing the aerodynamic influence coefficient (AIC) approach for both geometries. Results are confirmed by single passage flutter (SPF) simulations for specific interblade phase angles (IBPA) of interest. Finally, a unidirectional forced response analysis for the nominal and the blended rotor is conducted to determine the aerodynamic force exciting the blade motion. The frequency content as well as the forcing amplitudes is obtained from Fourier transformation of the forcing signal. As a result of the present analysis, the change of the blade vibration amplitude is computed.

Download Full-text

Review on the aerodynamics of intermediate compressor duct

JOURNAL OF MECHANICAL ENGINEERING AND SCIENCES ◽

10.15282/jmes.14.4.2020.13.0587 ◽

2020 ◽

Vol 14 (4) ◽

pp. 7446-7468

Author(s):

Manish Sharma ◽

Beena D. Baloni

Keyword(s):

High Pressure ◽

Pressure Loss ◽

Flow Analysis ◽

Outer Wall ◽

Optimization Techniques ◽

Optimum Pressure ◽

Research Areas ◽

Static Pressure Distribution ◽

High Pressure Compressor ◽

Pressure Compressor

In a turbofan engine, the air is brought from the low to the high-pressure compressor through an intermediate compressor duct. Weight and design space limitations impel to its design as an S-shaped. Despite it, the intermediate duct has to guide the flow carefully to the high-pressure compressor without disturbances and flow separations hence, flow analysis within the duct has been attractive to the researchers ever since its inception. Consequently, a number of researchers and experimentalists from the aerospace industry could not keep themselves away from this research. Further demand for increasing by-pass ratio will change the shape and weight of the duct that uplift encourages them to continue research in this field. Innumerable studies related to S-shaped duct have proven that its performance depends on many factors like curvature, upstream compressor’s vortices, swirl, insertion of struts, geometrical aspects, Mach number and many more. The application of flow control devices, wall shape optimization techniques, and integrated concepts lead a better system performance and shorten the duct length. This review paper is an endeavor to encapsulate all the above aspects and finally, it can be concluded that the intermediate duct is a key component to keep the overall weight and specific fuel consumption low. The shape and curvature of the duct significantly affect the pressure distortion. The wall static pressure distribution along the inner wall significantly higher than that of the outer wall. Duct pressure loss enhances with the aggressive design of duct, incursion of struts, thick inlet boundary layer and higher swirl at the inlet. Thus, one should focus on research areas for better aerodynamic effects of the above parameters which give duct design with optimum pressure loss and non-uniformity within the duct.

Download Full-text

Dry gas sealing solutions for high-pressure compressor applications

Proceedings of the Institution of Mechanical Engineers Part E Journal of Process Mechanical Engineering ◽

10.1177/0954408913489546 ◽

2013 ◽

Vol 228 (3) ◽

pp. 238-252 ◽

Cited By ~ 2

Author(s):

Ken Tacon ◽

Colin Twiss ◽

Vugar Mammadov ◽

Farhad Aslan-Zada

Keyword(s):

High Pressure ◽

High Pressure Compressor ◽

Pressure Compressor

Download Full-text

A Machine Learning Based Approach of Performance Estimation for High-Pressure Compressor Airfoils

Volume 2D: Turbomachinery ◽

10.1115/gt2018-75372 ◽

2018 ◽

Author(s):

Jonas Marx ◽

Stefan Gantner ◽

Jörn Städing ◽

Jens Friedrichs

Keyword(s):

Machine Learning ◽

High Pressure ◽

Machine Learning Algorithms ◽

Performance Estimation ◽

Predictive Maintenance ◽

Support Vector ◽

K Nearest Neighbor ◽

Operating Characteristics ◽

High Pressure Compressor ◽

Pressure Compressor

In recent years, the demands of Maintenance, Repair and Overhaul (MRO) customers to provide resource-efficient after market services have grown increasingly. One way to meet these requirements is by making use of predictive maintenance methods. These are ideas that involve the derivation of workscoping guidance by assessing and processing previously unused or undocumented service data. In this context a novel approach on predictive maintenance is presented in form of a performance-based classification method for high pressure compressor (HPC) airfoils. The procedure features machine learning algorithms that establish a relation between the airfoil geometry and the associated aerodynamic behavior and is hereby able to divide individual operating characteristics into a finite number of distinct aero-classes. By this means the introduced method not only provides a fast and simple way to assess piece part performance through geometrical data, but also facilitates the consideration of stage matching (axial as well as circumferential) in a simplified manner. It thus serves as prerequisite for an improved customary HPC performance workscope as well as for an automated optimization process for compressor buildup with used or repaired material that would be applicable in an MRO environment. The methods of machine learning that are used in the present work enable the formation of distinct groups of similar aero-performance by unsupervised (step 1) and supervised learning (step 2). The application of the overall classification procedure is shown exemplary on an artificially generated dataset based on real characteristics of a front and a rear rotor of a 10-stage axial compressor that contains both geometry as well as aerodynamic information. In step 1 of the investigation only the aerodynamic quantities in terms of multivariate functional data are used in order to benchmark different clustering algorithms and generate a foundation for a geometry-based aero-classification. Corresponding classifiers are created in step 2 by means of both, the k Nearest Neighbor and the linear Support Vector Machine algorithms. The methods’ fidelities are brought to the test with the attempt to recover the aero-based similarity classes solely by using normalized and reduced geometry data. This results in high classification probabilities of up to 96 % which is proven by using stratified k-fold cross-validation.

Download Full-text