Neuro-fuzzy approach for performance optimisation of variable nozzle turbofan engine

2005 ◽  
Vol 109 (1093) ◽  
pp. 139-146
Author(s):  
T. R. Nada ◽  
A. A. Hashem

AbstractAn algorithm employing adaptive neuro-fuzzy online identification and sequential quadratic programming optimisation techniques is developed to enhance aircraft engine performance. This algorithm is implemented and tested using digital simulation for two spool, mixed exhaust, variable geometry turbofan engine. Parametric study is conducted to select the proper measurable parameter that can represent the actual thrust during online optimisation. Subtractive clustering technique is applied to generate the minimum number of fuzzy rules that can model the engine performance at various input parameters and flight conditions. The resulting neuro-fuzzy system is then optimised through training algorithm to accurately represent the engine. This system can address engine variations by relearning the network using online measurements from the actual engine. Generating the optimum schedules and comparing them with those obtained from the complete non-linear engine model verify the algorithm. Benefits from this algorithm include fuel consumption savings, reductions in turbine inlet temperature, and preventing limit exceeding.

Author(s):  
Tashfeen Mahmood ◽  
Anthony Jackson ◽  
Vishal Sethi ◽  
Pericles Pilidis

This paper discusses thrust reversing techniques for a separate exhaust high bypass ratio turbofan engine and its effect on aircraft and engine performance. Cranfield University is developing suitable thrust reverser performance models. These thrust reverser performance models will subsequently be integrated within the TERA (Techno-economic Environmental Risk Analysis) architecture thereby allowing for more detailed and accurate representations of aircraft and engine performance during the landing phase of a typical civil aircraft mission. The turbofan engine chosen for this study was CUTS_TF (Cranfield University Twin Spool Turbofan) which is similar to the CFM56-5B4 engine and the information available in the public domain is used for the engine performance analysis along with the Gas Turbine Performance Software, ‘GasTurb 10’ [1]. The CUTEA (Cranfield University Twin Engine Aircraft) which is similar to the Airbus A320 is used alongside with the engine model for the thrust reverser performance calculations. The aim of this research paper is to investigate the effects on aircraft and engine performance characteristics due to the pivoting door type thrust reverser deployment. The paper will look into the overall engine performance characteristics and how the engine components get affected when the thrust reversers come into operation. This includes the changes into the operating point of fan, booster, HP compressor, HP turbine, LP turbine, bypass nozzle and core nozzle. Also, thrust reverser performance analyses were performed (at aircraft/engine system level) by varying the reverser exit area by ± 5% and its effect on aircraft deceleration rate, deceleration time and landing distances were observed.


Author(s):  
C. B. Wrong

An analysis of the market potential for a small turbofan engine intended for business aircraft has led to the design of the JT15D. The main design objectives were low initial cost, low fuel consumption, high reliability, low maintenance costs, ease of installation and operation, and good growth potential. These objectives have been achieved using a minimum number of components and providing a simple layout. Mounting of the engine is highly flexible, and operation is straightforward. Extensive component testing has been carried out. Guaranteed engine performance was achieved early in the development programme.


Author(s):  
Tashfeen Mahmood ◽  
Anthony Jackson ◽  
Syed H. Rizvi ◽  
Pericles Pilidis ◽  
Mark Savill ◽  
...  

This paper discusses thrust reverser techniques for a mixed exhaust high bypass ratio turbofan engine and its effect on aircraft and engine performance. The turbofan engine chosen for this study was CUTS_TF (Cranfield University Three Spool Turbofan) which is similar to Rolls-Royce TRENT 772 engine and the information available for this engine in the public domain is used for the engine performance analysis along with the Gas Turbine Performance Software, GasTurb 10. The CUTEA (Cranfield University Twin Engine Aircraft) which is similar to the Airbus A330 is used along side with the engine model for the thrust reverser performance calculations. The aim of this research paper is to investigate the effects on mixed exhaust engine performance due to the pivoting door type thrust reverser deployment. The paper looks into the engine off-design performance characteristics and how the engine components get affected when the thrust reverser come into operation. This includes the changes into the operating point of fan, IP compressor, HP compressor, HP turbine, IP turbine, LP turbine and the engine exhaust nozzle. Also, the reverser deployment effect on aircraft, deceleration time and landing distances are discussed.


Author(s):  
R. H. Smith ◽  
J. D. Chisholm ◽  
J. F. Stewart

An adaptive, integrated flight/propulsion control algorithm called Performance Seeking Control (PSC) has been developed to optimize total aircraft performance during steady state engine operation. The multi-mode algorithm will minimize fuel consumption at cruise conditions; maximize excess thrust (thrust minus drag) during aircraft accelerations, climbs, and dashes; and extend engine life by reducing Fan Turbine Inlet Temperature (FTIT) when the extended life mode is engaged. On-board models of the inlet, engine, and nozzle are optimized to compute a set of control trims, which are then applied as increments to the nominal engine and inlet control schedules. The on-board engine model is continually updated to match the operating characteristics of the actual engine cycle through the use of a Kalman filter, which accounts for anomalous engine operation. The PSC algorithm will be flight demonstrated on an F-15 test aircraft under the direction of the NASA Ames/Dryden Flight Research Facility. This paper discusses the PSC design strategy, describes the control algorithm, and presents results from high fidelity, nonlinear aircraft/engine simulations. Simulation results indicate that thrust increases as high as 15% and specific fuel consumption reductions up to 3% are realizable by the PSC system.


Author(s):  
M. S. Zawislak ◽  
D. J. Cerantola ◽  
A. M. Birk

A high bypass ratio turbofan engine capable of powering the Boeing 757 was considered for thrust and drag analysis. A quasi-2D engine model applying the fundamental thermodynamics conservation equations and practical constraints determined engine performance and provided cross-sectional areas in the low-pressure system. Coupled with suggestions on boat-tail angle and curvature from literature, a representative bypass duct and primary exhaust nozzle was created. 3D steady-RANS simulations using Fluent® 18 were performed on a 1/8th axisymmetric section of the geometry. A modified 3D fan zone model forcing radial equilibrium was used to model the fan and bypass stator. Takeoff speed and cruise operating conditions were modeled and simulated to identify changes in thrust composition and intake sensitivity. Comparison between net thrust predictions by the engine model and measured in CFD were within grid uncertainty and model sensitivity at cruise. Trends observed in a published database were satisfied and calculations coincided with GasTurb™ 8.0. Verification of thrust in this manner gave confidence to the aerodynamic performance prediction of this modest CFD. Obtaining a baseline bypass design would allow rapid testing of aftermarket components and integration techniques in a realistic flow-field without reliance on proprietary engine data.


2021 ◽  
Author(s):  
Julian Salomon ◽  
Jan Göing ◽  
Sebastian Lück ◽  
Matteo Broggi ◽  
Jens Friedrichs ◽  
...  

Abstract In this work the impact of combined module variances on the overall performance of a high-bypass aircraft engine is investigated. Therefore, a comprehensive sensitivity analysis on the example of a turbofan engine performance model is provided by means of Kucherenko indices. Direct influences of selected model inputs on key model outputs as well as influences due to interaction effects between these input variables are identified. The selected input variables of the performance model are partly subject to considerable dependencies that are taken into account by the Kucherenko indices. The results confirm known direct influences of deterioration effects on the key performance parameters of the aircraft engine on the one hand, and provide profound insights into complex interaction effects between the components and their impact on the V2500-A1 aircraft engine performance on the other.


Author(s):  
Tobias Wensky ◽  
Lutz Winkler ◽  
Jens Friedrichs

Environmental influences have an increasing effect on the performance degradation and durability of modern aircraft engines. The study provides information on environmental effects using in-flight engine data and results of engine overhauls performed at MTU Maintenance. According to these investigations global regions are classified into erosive and anthropogenic polluted areas. Both types of regional effects significantly degrade performance and engine durability. The investigation, which is based upon the in-flight data taken from Engine Trend Monitoring (ETM), provides one approach for the estimatation of environmental effects on aircraft engine performance degradation. The results of the monitored engines provide detailed information on the environmental effects atlocal airports. The Exhaust Gas Temperature (EGT) that has been measured under flight conditions is compared with a calculated EGT of a calibrated fully thermodynamic gas path engine model (MOPS). Therefore, the EGT also serves as an indicator for performance degradation, increase of specific fuel consumption and the need for on-wing maintenance actions. Further information provided by the engine shop visit data at MTU Maintenance allows for an estimation of environmental influences on durability and overhaul costs. The on-wing time of maintained shop visit data is compared with a model for on-wing time calculation, whereas variations in durability were observed and analyzed under the aspects of environmental influences. Depending on the variations, corrections were made by defining the factors contributing to the classifications of environmental effects. These corrective factors provide information on reduced durability and increased operating costs. The result of the ETM performance degradation analysis shows significant variations in engine performance degradation as a result of specific regional operation. The analyses of maintenance data as well as performance degradation measured by ETM show remarkable environmental effects on engine durability and an increase in maintenance costs.


Author(s):  
Stanislaus Reitenbach ◽  
Alexander Krumme ◽  
Thomas Behrendt ◽  
Markus Schnös ◽  
Thomas Schmidt ◽  
...  

The purpose of this paper is to present a multidisciplinary predesign process and its application to three aero-engine models. First, a twin spool mixed flow turbofan engine model is created for validation purposes. The second and third engine models investigated comprise future engine concepts: a counter rotating open rotor (CROR) and an ultrahigh bypass turbofan. The turbofan used for validation is based on publicly available reference data from manufacturing and emission certification. At first, the identified interfaces and constraints of the entire predesign process are presented. An important factor of complexity in this highly iterative procedure is the intricate data flow, as well as the extensive amount of data transferred between all involved disciplines and among different fidelity levels applied within the design phases. To cope with the inherent complexity, data modeling techniques have been applied to explicitly determine required data structures of those complex systems. The resulting data model characterizing the components of a gas turbine and their relationships in the design process is presented in detail. Based on the data model, the entire engine predesign process is presented. Starting with the definition of a flight mission scenario and resulting top level engine requirements, thermodynamic engine performance models are developed. By means of these thermodynamic models, a detailed engine component predesign is conducted. The aerodynamic and structural design of the engine components are executed using a stepwise increase in level of detail and are continuously evaluated in context of the overall engine system.


Author(s):  
P. Dewallef ◽  
O. Le´onard ◽  
K. Mathioudakis

The purpose of this contribution is to apply ridge regression to Kalman filtering in order to stabilize a health parameter identification under low or negative redundancy. The resulting algorithm achieves a so-called soft-constrained recursive health parameter identification, i.e. constraints are applied to parameters in a statistical way, contrary to hard-constrained algorithms based on strong equality or inequality constrains. The method is tested on data generated by a steady state turbofan engine model and representing typical component faults. The benefits that can be realized in terms of stability and accuracy are highlighted and some limits of the method are also mentioned.


Author(s):  
Myoungcheol Kang ◽  
Stephen Ogaji ◽  
Pericles Pilidis ◽  
Changduk Kong

This study presents a detailed analysis of aircraft engine maintenance cost based on the relationships between engine performance and geometric parameters. Estimating engine maintenance cost is very complicated and depends upon empirical work based on know-how and huge database to develop the industrial cost estimation program. Engine maintenance costs are basically influenced by the shop visit rates (SVR), the workscope of each shop visit, the shop visit pattern and the manhours and materials used in each shop visit. To estimate these values for a specific engine model, there is a need to develop the empirical correlations of engine maintenance. For this study, an engine performance and maintenance database was created. The engine performance data for each major component were simulated by an engine performance code, TURBOMATCH developed at Cranfield University, U.K., at static sea-level condition and geometric data were collected from open literature. Also, engine maintenance cost data for some current engines were collected and used. Some trend line equations based on the database were developed for the estimation of shop-visit interval, work-scope, Man-Hours, material cost and Life Limited Part cost. Comparisons of the results between trend equations and original data were carried out. The results show that this approach can give a more reasonable and detailed estimation of engine maintenance cost than older empirical methods.


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