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

2019 ◽  
Vol 123 (1260) ◽  
pp. 230-247 ◽  
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.

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

2014 ◽  
Author(s):  
Alain Batailly ◽  
Mathias Legrand ◽  
Antoine Millecamps ◽  
Sèbastien 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.

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

2014 ◽  
Vol 137 (2) ◽  
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.

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

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.

scholarly journals Influence of combined compressor and turbine deterioration on the overall performance of a jet engine using RANS simulation and Pseudo Bond Graph approach

2020 ◽  
Vol 4 ◽  
pp. 296-308
Author(s):  
Jan Goeing ◽  
Hendrik Seehausen ◽  
Vladislav Pak ◽  
Sebastian Lueck ◽  
Joerg R. Seume ◽  
...  
Keyword(s):  
High Pressure ◽  
Differential Equations ◽  
Tip Clearance ◽  
System Stability ◽  
Simplified Model ◽  
Jet Engine ◽  
High Pressure Compressor ◽  
Overall Performance ◽  
The Impact ◽  
Pressure Compressor

In this study, numerical models are used to analyse the influence of isolated component deterioration as well as the combination of miscellaneous deteriorated components on the transient performance of a high-bypass jet engine. For this purpose, the aerodynamic impact of major degradation effects in a high-pressure compressor (HPC) and turbine (HPT) is modelled and simulated by using 3D CFD (Computational Fluid Dynamics). The impact on overall jet engine performance is then modelled using an 1D Reduced Order Model (ROM). Initially, the HPC performance is investigated with a typical level of roughness on vanes and blades and the HPT performance with an increasing tip clearance. Subsequently, the overall performance of the jet engines with the isolated and combined deteriorated domains is computed by the in-house 1D performance tool ASTOR (AircraftEngine Simulation for Transient Operation Research). Degradations have a significant influence on the system stability and transient effects. In ASTOR, a system of differential equations including the equations of motion and further ordinary differential equations is solved. Compared to common ROMs, this enables a higher degree of accuracy. The results of temperature downstream of the high-pressure compressor and low-pressure turbine as well as the specific fuel composition and the HP rotational speed are used to estimate the degree and type of engine deterioration. However, the consideration of the system stability is necessary to analyse the characterisation in more detail. Finally, a simplified model which merges two engines with individual deteriorated domains into one combined deteriorated engine, is proposed. The simplified model predicts the performance of an engine which has been simulated with combined deteriorated components.

Influence of Non-Uniform OGV on High Pressure Compressor Performance

2013 ◽  
Author(s):  
Ping Yang ◽  
Weiliang Xie ◽  
Feng Xu ◽  
Jinzhang Feng
Keyword(s):  
High Pressure ◽  
Flow Field ◽  
Incidence Angle ◽  
Thickness Distribution ◽  
Iteration Process ◽  
Optimized Design ◽  
Suction Surface ◽  
High Pressure Compressor ◽  
The Impact ◽  
Pressure Compressor

Generally, the outlet guide vanes (OGV) of a high pressure compressor (HPC) have a single vane profile and are placed uniformly circumferentially. However, in some situations, portions of the OGV are thickened to be accommodated to some special requirements which may result in negative influences on the HPC performance. This paper describes the design of a non-uniform OGV row of a multi-stage HPC. The OGV is periodically composed of one thick vane and two thin vanes. A series of vanes are selected by changing vane geometry parameters including vane stagger and camber, location of maximum thickness, thickness distribution, chord length and vane circumference position. Numerical simulations of these different non-uniform OGV rows along with the same rotor upstream are carried out to evaluate the impact of these parameters on the non-uniform OGV performance. Through this “manual-iteration” process, the best configuration is selected as the final “optimized” design. The results show that, firstly, it is beneficial to set the suction surface incidence angle of the thick airfoils the same with that of the thin airfoils for uniform incoming flow field; secondly, the divergence rate of passage should be carefully controlled to reduce the loss coefficient; thirdly, the vane circumference position should be adjusted to keep the mass flow of each passage being equal to ensure uniformity of the outlet flow field. Finally, it is demonstrated that after optimization, the adverse effects of the non-uniform OGV on the whole HPC performance can be nearly eliminated.

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

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.

Design of Experiments and Numerical Simulation of Deteriorated High Pressure Compressor Airfoils

2016 ◽  
Author(s):  
Gerald Reitz ◽  
Stephan Schlange ◽  
Jens Friedrichs
Keyword(s):  
High Pressure ◽  
Design Of Experiments ◽  
Repair Process ◽  
Aerodynamic Performance ◽  
Geometric Properties ◽  
Meta Model ◽  
High Pressure Compressor ◽  
The Impact ◽  
Actual Geometry ◽  
Pressure Compressor

During the operation of a jet engine, deterioration occurs. This constantly affects the engine performance parameters like exhaust gas temperature (EGT) and thrust specific fuel consumption (TSFC). If the EGT reaches a given limit, the engine has to be overhauled during a shop visit at a MRO company (Maintenance, Repair and Overhaul). Using the example of the high pressure compressor (HPC), the airfoils get analyzed for a few geometric properties and classified as serviceable, repairable and non-repairable. The repairable airfoils go through a repair process without in detail considering the actual geometry. To improve the repair process, tailored maintenance actions are desirable. For this purpose, the aerodynamic properties of the airfoil shall be the key factor for defining the repair actions. Therefore, geometric properties with high influence on the aerodynamic performance have to be known to reduce the amount of measuring time. This paper will present a Design of Experiments (DoE) for HPC-airfoil geometry variations. Therefore, 550 different stage setups will be generated, simulated and analyzed. The database will be imported to a Kriging Method to generate a meta-model. Afterwards, the impact of the different geometric properties on the aerodynamic performance, like pressure-, work- and loss coefficients, will be analyzed by using the meta-model. The most important parameters will be determined and their impact on the flow will be explained.

Review on the aerodynamics of intermediate compressor duct

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.

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