Numerical Investigations of a High Pressure Compressor Exposed to Unsteady Pressure Gain Combustion Employing Data-Driven Methods

2021 ◽  
Author(s):  
Victor Bicalho Civinelli de Almeida ◽  
Dieter Peitsch
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Data Driven ◽  
Thermodynamic Efficiency ◽  
Dynamic Mode ◽  
Numerical Work ◽  
High Pressure Compressor ◽  
Pressure Gain Combustion ◽  
Flow Features ◽  
Pressure Compressor

Abstract Pressure gain combustion (PGC) should substantially improve the thermodynamic efficiency of gas turbines by increasing the fluid total pressure as it traverses the combustion chamber. However, PGC introduces additional unsteadiness to the intrinsically complex turbomachinery flow. A high pressure compressor, located right upstream of the PGC section, is therefore constantly exposed to flow fluctuations, experiencing drop in efficiency, increase in pressure loss as well as higher stalling and structural failure risks. This numerical work analyzes how one stage of a well-established engine, namely the NASA EEE core compressor, reacts to the disturbances induced by the potential implementation of PGC. Unsteady computational fluid dynamics are employed with boundary conditions simulating the combustion unsteadiness. The main focus of the current paper is the application of data-driven methods, including the proper orthogonal decomposition (POD) and the dynamic mode decomposition (DMD), when comparing the high pressure compressor baseline operation with the PGC-disturbed case. Representative flow features and their frequency content, not identifiable with typical methods such as phase-averaging, are easily extracted from snapshots sequences. The results not only allow the identification of the most relevant coherent structures present in the unsteady flow, but also show how they change in the presence of PGC. This contribution sheds light on how novel PGC technology can be integrated with turbomachinery components, identifying modifications in the main flow features with the use of advanced decomposition techniques.

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.

Form Factor for the Top-Level Comparison of the Condition of Supply of High-Pressure Compressor Blades

2012 ◽  
Author(s):  
Marcus Schrade ◽  
Stephan Staudacher ◽  
Matthias Weißschuh ◽  
Matthias Voigt
Keyword(s):  
High Pressure ◽  
Form Factor ◽  
Gas Turbines ◽  
Principal Component ◽  
Complex Geometries ◽  
Compressor Blades ◽  
High Pressure Compressor ◽  
Geometric Deviations ◽  
Pressure Compressor ◽  
Component Feature

High-pressure compressor (HPC) performance and maintenance of gas turbines is influenced by blade production scatter and in-service deterioration. Complex geometries in HPC, especially at blades, yield to a large amount of component features, which individually influence performance and maintenance characteristics. This results in a highly complex and poorly observable system. Hence, the correlation of a single component feature to performance or maintenance characteristics is not purposeful and a reduction of the parameter space is advantageous. A form factor is introduced that reduces geometric deviations of component features to a scalar. Principal component analysis (PCA) of measured HPC blades is used to support the form factor concept. The meaningfulness of this approach is shown in identifying process capabilities of different forges based on the form factor.

scholarly journals Part Load Performance of the Intercooled Two-Shaft Gas Turbine With Power Output at Constant Speed on the High-Pressure Shaft

1987 ◽  
Author(s):  
N. Gasparovic ◽  
J.-W. Kim
Keyword(s):  
High Pressure ◽  
Power Output ◽  
Gas Turbines ◽  
Internal Heat ◽  
Constant Speed ◽  
Inlet Temperature ◽  
Part Load ◽  
Internal Heat Exchanger ◽  
High Pressure Compressor ◽  
Pressure Compressor

The general analysis of the part load performance of gas turbines indicates that the intercooled cycle with two shafts and power output at constant speed on the high-pressure shaft can have a good part load efficiency. Calculations with fixed geometry of the turbomachines show an intolerable increase of the turbine inlet temperature above the permissible level. By introducing variable geometry in the turbomachines, this disadvantage can be overcome. With variable inlet guide vanes at the high-pressure compressor an excellent part load performance is achieved. Further improvements are possible by adding an internal heat exchanger.

Numerical Investigation of Vortex Reducer Flows in the High Pressure Compressor of Modern Aeroengines

2002 ◽  
Author(s):  
Dieter Peitsch ◽  
Manuela Stein ◽  
Stefan Hein ◽  
Reinhard Niehuis ◽  
Ulf Reinmo¨ller
Keyword(s):  
High Pressure ◽  
Gas Turbines ◽  
Efficient Operation ◽  
Pressure Losses ◽  
High Pressure Compressor ◽  
Air System ◽  
The Difference ◽  
Secondary Air ◽  
Set Up ◽  
Pressure Compressor

Modern jet engines require very high cycle temperatures for efficient operation. In turn, cooling air is needed for the turbine, since the materials are not yet capable of taking these temperatures. Air is taken from the compressor for the purpose of cooling and turbine rim sealing, bypassing the main combustion circuit. Since this affects the efficiency of the engine in a negative manner, measures are taken to reduce the amount of air to an absolute minimum. These measures include the investigation of reducing pressure losses within the involved subsystems. One of these subsystems in the BR700 aeroengine series of Rolls-Royce is the vortex reducer device, which delivers bleed air to the secondary air system of the engine. The German government has set up a research project, aiming for an overall improvement of aeroengines. This program, Engine 3E, where 3E reflects Efficiency, Economy and Environment, concentrates on the main components of gas turbines. Programmes for the high pressure turbine and for the combustion chamber have been set up. The high pressure compressor has been identified as key component as well. A new 9-stage compressor is being developed at Rolls-Royce Deutschland to adress the respective needs. From the point of view of the secondary air system, the vortex reducer in this component plays a major role with respect to the efficient use of cooling and sealing air. Rolls-Royce Deutschland has performed CFD studies on the performance of different vortex reducer geometries, which currently are considered for incorporation into the future engine. The results of these investigations wil be converted into more simple design rules for proper reflection of the behaviour of this system for future designs. The paper presents the set up of the geometries, the applied boundary conditions as well as the final results. To tackle the difference between a high pressure compressor rig and a typical two-shaft engine, a dedicated investigation to assess the difference between a pure high pressure core without an internal shaft and a realistic high/low pressure shaft configuration has been carried out and is included in the paper. Recommendations to improve the design with respect to minimized pressure losses will be shown as well.

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.

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.

Hybrid Model-Based and Data-Driven Diagnostic Algorithm for Gas Turbine Engines

2020 ◽  
Author(s):  
Amare Fentaye ◽  
Valentina Zaccaria ◽  
Moksadur Rahman ◽  
Mikael Stenfelt ◽  
Konstantinos Kyprianidis
Keyword(s):  
High Pressure ◽  
Measurement Uncertainty ◽  
Gas Turbine ◽  
Diagnostic Algorithm ◽  
Data Driven ◽  
Intermediate Pressure ◽  
Path Component ◽  
Fault Diagnostic ◽  
Component Faults ◽  
Pressure Compressor

Abstract Data-driven algorithms require large and comprehensive training samples in order to provide reliable diagnostic solutions. However, in many gas turbine applications, it is hard to find fault data due to proprietary and liability issues. Operational data samples obtained from end-users through collaboration projects do not represent fault conditions sufficiently and are not labeled either. Conversely, model-based methods have some accuracy deficiencies due to measurement uncertainty and model smearing effects when the number of gas path components to be assessed is large. The present paper integrates physics-based and data-driven approaches aiming to overcome this limitation. In the proposed method, an adaptive gas path analysis (AGPA) is used to correct measurement data against the ambient condition variations and normalize. Fault signatures drawn from the AGPA are used to assess the health status of the case engine through a Bayesian network (BN) based fault diagnostic algorithm. The performance of the proposed technique is evaluated based on five different gas path component faults of a three-shaft turbofan engine, namely intermediate-pressure compressor fouling (IPCF), high-pressure compressor fouling (HPCF), high-pressure turbine erosion (HPTE), intermediate-pressure turbine erosion (IPTE), and low-pressure turbine erosion (LPTE). Robustness of the method under measurement uncertainty has also been tested using noise-contaminated data. Moreover, the fault diagnostic effectiveness of the BN algorithm on different number and type of measurements is also examined based on three different sensor groups. The test results verify the effectiveness of the proposed method to diagnose single gas path component faults correctly even under a significant noise level and different instrumentation suites. This enables to accommodate measurement suite inconsistencies between engines of the same type. The proposed method can further be used to support the gas turbine maintenance decision-making process when coupled with overall Engine Health Management (EHM) systems.

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

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.

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