Experimental Evaluation of Heavy Fan-High-Pressure Compressor Interaction in a Three-Shaft Engine: Part 1—Experimental Setup and Results

1985 ◽  
Vol 107 (4) ◽  
pp. 828-832 ◽  
Author(s):  
A. Scha¨ffler ◽  
D. C. Miatt
Keyword(s):  
High Pressure ◽  
Rotating Stall ◽  
Line System ◽  
Surge Margin ◽  
High Pressure Compressor ◽  
Engine Part ◽  
Aerodynamic Interaction ◽  
Compressor Surge ◽  
Sector Angle ◽  
Pressure Compressor

Severe aerodynamic interaction between the fan core stream section and the high-pressure compressor of a three-shaft low-bypass-ratio engine is described. At high fan running lines a heavy single-cell rotating stall was found in the fan core stream even at high aerodynamic speeds between 90–98%. The rotating circumferential distortion with 180–200 deg sector angle is swallowed by the intermediate pressure compressor but erodes the high-pressure compressor surge margin by about 22%, leading to steady-state surges. A remotely mounted transducer in a specific arrangement was used successfully for measurements in the hot environment behind intermediate and high-pressure compressor using a so-called “long-line” system with a closed end at the downstream pipe.

Experimental Evaluation of Heavy Fan-High-Pressure Compressor Interaction in a Three-Shaft Engine: Part II—Analysis of Distortion and Fan Loading

1986 ◽  
Vol 108 (1) ◽  
pp. 171-174
Author(s):  
A. Scha¨ffler ◽  
D. C. Miatt
Keyword(s):  
High Pressure ◽  
Rotating Stall ◽  
Interesting Insight ◽  
High Pressure Compressor ◽  
Engine Part ◽  
Distortion Analysis ◽  
Core Section ◽  
Sector Angle ◽  
Insight Into ◽  
Pressure Compressor

Analysis of a severe rotating-stall phenomenon encountered in the fan core section of a three-shaft low bypass engine revealed interesting insight into the growth and circumferential extension of the stall cells immediately before surge of the high-pressure compressor was induced. The effect of a rotating distortion in contrast to the usually encountered stationary distortion is highlighted. The rotating distortion changes the time and hence the effectively felt distortion sector angle depending on a co- or contra-rotational arrangement of the distorting and the distorted compressor. The analysis shows that a contra-rotational arrangement provides a more stable and tolerant situation against that type of distortion. Analysis of the fan loading shows the static temperature rise coefficient to be the most descriptive for the fan rotor 1 hub section which initiated the rotating-stall mechanism.

Aerodynamic Loading Considerations of Three-Shaft Engine Compression System During Surge

2020 ◽  
Author(s):  
Jose Moreno ◽  
John Dodds ◽  
Christopher Sheaf ◽  
Fanzhou Zhao ◽  
Mehdi Vahdati
Keyword(s):  
High Pressure ◽  
Physical Explanation ◽  
Compression System ◽  
High Pressure Compressor ◽  
Aero Engine ◽  
Compressor Surge ◽  
The Moment ◽  
Engine Components ◽  
Variable Stator ◽  
Pressure Compressor

Abstract Compressor surge imposes a limit on aero-engine operability and can compromise integrity because of significant aerodynamic loads imparted on the engine components. The aim of this paper is to use 3D unsteady CFD to predict the surge loadings on a modern three spool engine. The computations are performed using a whole-assembly approach. In this work, the effect of two types of surge initiation on the maximum loading recorded during surge are studied and a physical explanation of the main phenomena which contribute to those loadings is offered. The engine is matched at a high power condition and the surge inception is via throttling of the high pressure compressor (HPC) or turning of the intermediate pressure compressor (IPC) variable stator vanes. It was found that in an aero-engine surge event, the maximum overpressure are caused by a combined effect of the surge shock wave passing and high pressure gas blown towards the front of the engine during depressurisation. The overpressure is dictated by the compression system exit pressure at the moment of the surge inception. The surge initiation via HPC throttling produces larger overpressure and therefore, should be considered for design considerations.

Aerodynamic Loading Considerations of Three-Shaft Engine Compression System During Surge

2021 ◽  
pp. 1-31
Author(s):  
Jose Moreno ◽  
John Dodds ◽  
Christopher T. J. Sheaf ◽  
Fanzhou Zhao ◽  
Mehdi Vahdati
Keyword(s):  
High Pressure ◽  
Physical Explanation ◽  
Compression System ◽  
High Pressure Compressor ◽  
Aero Engine ◽  
Compressor Surge ◽  
The Moment ◽  
Engine Components ◽  
Variable Stator ◽  
Pressure Compressor

Abstract Compressor surge imposes a limit on aero-engine operability and can compromise integrity because of significant aerodynamic loads imparted on the engine components. The aim of this paper is to use 3D unsteady CFD to predict the surge loadings on a modern three spool engine. The computations are performed using a whole-assembly approach. In this work, the effect of two types of surge initiation on the maximum loading recorded during surge are studied and a physical explanation of the main phenomena which contribute to those loadings is offered. The engine is matched at a high power condition and the surge inception is via throttling of the high pressure compressor (HPC) or turning of the intermediate pressure compressor (IPC) variable stator vanes. It was found that in an aero-engine surge event, the maximum overpressure are caused by a combined effect of the surge shock wave passing and high pressure gas blown towards the front of the engine during depressurisation. The overpressure is dictated by the compression system exit pressure at the moment of the surge inception. The surge initiation via HPC throttling produces larger overpressure and therefore, should be considered for design considerations.

High Pressure Compressor Stabilization by Controlled Pulsed Injection

2012 ◽  
Author(s):  
Sven-Jürgen Hiller ◽  
Jakob Hermann ◽  
Robert Widhopf-Fenk
Keyword(s):  
High Pressure ◽  
Mass Flow ◽  
Stability Control ◽  
Stable Operation ◽  
Surge Margin ◽  
High Pressure Compressor ◽  
Stability Control System ◽  
Pulsed Injection ◽  
Tip Injection ◽  
Pressure Compressor

Steady tip injection with re-circulated air as a reliable method for high pressure compressor stabilization has the disadvantage to reduce the efficiency due to the usage of already compressed air. Therefore, the minimization of recirculation air and/or a large extension of the stable operation range is mandatory. The paper describes an alternative approach by using an active compressor stability control system with modulating valves. The system was tested at a high pressure compressor. It recognized evolving stall cells reliable. The achieved available stable throttling range of the compressor (in terms of mass flow) was more than doubled by active controlled injection compared to steady tip injection at 90% aerodynamic speed. The other way round, depending on the tip flow structure and the aerodynamic speed injection mass flow saving up to 50% at a similar surge margin compared to steady injection was achieved.

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.

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.

Elimination of unstable free vibrations of the rotor of a centrifugal high-pressure compressor

1988 ◽  
Vol 24 (7) ◽  
pp. 356-360
Author(s):  
V. B. Shnepp ◽  
A. M. Galeev ◽  
G. S. Batkis ◽  
V. M. Polyakov
Keyword(s):  
High Pressure ◽  
Free Vibrations ◽  
High Pressure Compressor ◽  
Pressure Compressor
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