Validation of a Mixed Flow Turbofan Performance Model in the Sub-Idle Operating Range

2003 ◽  
Author(s):  
Claus Riegler ◽  
Michael Bauer ◽  
Holger Schulte
Keyword(s):  
Steady State ◽  
Engine Performance ◽  
Performance Model ◽  
Maximum Power ◽  
Development Programs ◽  
Mixed Flow ◽  
Typical Application ◽  
Operating Range ◽  
Engine Model ◽  
Lighting Conditions

During turbofan development programs the evaluation of steady-state and transient engine performance is usually achieved by applying full thermodynamic engine models at least in the operating range between idle and maximum power conditions, but more recently also in the sub-idle operating range, e.g. for steady-state windmilling behavior and for starting, relight and shut down scenarios. The paper describes the setup, and in more detail the validation, of a full thermodynamic engine model for a two-spool mixed flow afterburner turbofan which is capable to run from maximum power down to zero speed and zero flow conditions in steady-state and transient mode. The validation is performed by using the model-based performance analysis procedure called ANSYN even in windmilling operation. Once the steady-state sub-idle model is validated the extension to transient sub-idle capability is achieved by simply adding the effects of rotor moment of inertia of the spools, while heat soakage effects are rather negligible without heat release in the burner. Especially lighting conditions in the burner are produced by such a validated sub-idle model inherently due to reliable data calculated at the burner entry station. The variety of applications of a validated full thermodynamic engine model is large. The performance data delivered is highly reliable and very consistent because the full operating range of the engine is covered with one model, and by appropriate means of speeding up the calculation even real-time capability may be achieved. In the paper synthesized data for an engine dry crank is compared to real engine test data as one typical application.

Development and Integration of Rain Ingestion Effects in Engine Performance Simulations

2014 ◽  
Vol 137 (4) ◽  
Author(s):  
I. Roumeliotis ◽  
A. Alexiou ◽  
N. Aretakis ◽  
G. Sieros ◽  
K. Mathioudakis
Keyword(s):  
Engine Performance ◽  
Velocity Slip ◽  
Droplet Surface ◽  
Performance Model ◽  
Droplet Breakup ◽  
Test Case ◽  
Case Scenario ◽  
Worst Case ◽  
Engine Model ◽  
Component Models

Rain ingestion can significantly affect the performance and operability of gas turbine aero-engines. In order to study and understand rain ingestion phenomena at engine level, a performance model is required that integrates component models capable of simulating the physics of rain ingestion. The current work provides, for the first time in the open literature, information about the setup of a mixed-fidelity engine model suitable for rain ingestion simulation and corresponding overall engine performance results. Such a model can initially support an analysis of rain ingestion during the predesign phase of engine development. Once components and engine models are validated and calibrated versus experimental data, they can then be used to support certification tests, the extrapolation of ground test results to altitude conditions, the evaluation of control or engine hardware improvements and eventually the investigation of in-flight events. In the present paper, component models of various levels of fidelity are first described. These models account for the scoop effect at engine inlet, the fan effect and the effects of water presence in the operation and performance of the compressors and the combustor. Phenomena such as velocity slip between the liquid and gaseous phases, droplet breakup, droplet–surface interaction, droplet and film evaporation as well as compressor stages rematching due to evaporation are included in the calculations. Water ingestion influences the operation of the components and their matching, so in order to simulate rain ingestion at engine level, a suitable multifidelity engine model has been developed in the Proosis simulation platform. The engine model's architecture is discussed, and a generic high bypass turbofan is selected as a demonstration test case engine. The analysis of rain ingestion effects on engine performance and operability is performed for the worst case scenario, with respect to the water quantity entering the engine. The results indicate that rain ingestion has a strong negative effect on high-pressure compressor surge margin, fuel consumption, and combustor efficiency, while more than half of the water entering the core is expected to remain unevaporated and reach the combustor in the form of film.

Advanced Controls for Fuel Consumption and Time-on-Wing Optimization in Commercial Aircraft Engines

2007 ◽  
Author(s):  
Daniel Viassolo ◽  
Aditya Kumar ◽  
Brent Brunell
Keyword(s):  
Steady State ◽  
Fuel Consumption ◽  
Flight Control ◽  
Operation Mode ◽  
Engine Performance ◽  
Current Control ◽  
Model Parameters ◽  
Transient Operation ◽  
Engine Model ◽  
Flight Envelope

This paper introduces an architecture that improves the existing interface between flight control and engine control. The architecture is based on an on-board dynamic engine model, and advanced control and estimation techniques. It utilizes a Tracking Filter (TF) to estimate model parameters and thus allow a nominal model to match any given engine. The TF is combined with an Extended Kalman Filter (EKF) to estimate unmeasured engine states and performance outputs, such as engine thrust and turbine temperatures. These estimated outputs are then used by a Model Predictive Control (MPC), which optimizes engine performance subject to operability constraints. MPC objective and constraints are based on the aircraft operation mode. For steady-state operation, the MPC objective is to minimize fuel consumption. For transient operation, such as idle-to-takeoff, the MPC goal is to track a thrust demand profile, while minimizing turbine temperatures for extended engine time-on-wing. Simulations at different steady-state conditions over the flight envelope show important fuel savings with respect to current control technology. Simulations for a set of usual transient show that the TF/EKF/MPC combination can track a desired transient thrust profile and achieve significant reductions in peak and steady-state turbine gas and metal. These temperature reductions contribute heavily to extend the engine time-on-wing. Results for both steady state and transient operation modes are shown to be robust with respect to engine-engine variability, engine deterioration, and flight envelope operating point conditions. The approach proposed provides a natural framework for optimal accommodation of engine faults through integration with fault detection algorithms followed by update of the engine model and optimization constraints consistent with the fault. This is a potential future work direction.

Dynamic Simulation of Road Vehicle Performance Under Transient Accelerating Conditions

1996 ◽  
Vol 210 (1) ◽  
pp. 11-21 ◽  
Author(s):  
C-W Hong
Keyword(s):  
Steady State ◽  
Dynamic Simulation ◽  
Thermal Inertia ◽  
Engine Performance ◽  
Reconstruction Method ◽  
Passenger Cars ◽  
Road Vehicle ◽  
Vehicle Performance ◽  
Inertia Effects ◽  
Engine Model

A personal computer-based simulation package has been developed to design the powertrain system of passenger cars aiming to operate at optimal performance. This package is capable of dynamic simulation of road vehicle performance under transient accelerating conditions. Two methods are included: one is the traditional transient-reconstruction method using steady-state engine performance maps; the other is a dynamic simulation technique newly developed by the author. The latter is described in this paper. It is based on cyclic analysis of the engine thermofluid-combustion phenomena with additional considerations of flow inertia, thermal inertia and mechanical inertia effects. This transient engine model plus a dynamic powertrain model and a transient road-load simulation make it possible to predict the automobile performance under road-driving conditions. Two examples of transient performance prediction, including a sudden full-throttle acceleration at a fixed gear and a changing-gear starting acceleration from standstill, are demonstrated in this paper. These examples show that the relation between the engine speed and the road speed under accelerating conditions is very different to the steady-state relationships normally assumed.

Sensitivity Analysis of an Aircraft Engine Model Under Consideration of Dependent Variables

2021 ◽  
Author(s):  
Julian Salomon ◽  
Jan Göing ◽  
Sebastian Lück ◽  
Matteo Broggi ◽  
Jens Friedrichs ◽  
...  
Keyword(s):  
Sensitivity Analysis ◽  
Engine Performance ◽  
Aircraft Engine ◽  
Interaction Effects ◽  
Performance Model ◽  
Engine Model ◽  
Overall Performance ◽  
Input Variables ◽  
The One ◽  
The Impact

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.

Effects of Anti-Icing System Operation on Gas Turbine Performance and Monitoring

2001 ◽  
Author(s):  
K. Mathioudakis ◽  
A. Tsalavoutas
Keyword(s):  
Gas Turbine ◽  
Engine Performance ◽  
Performance Model ◽  
False Alarms ◽  
System Operation ◽  
Diagnostic Ability ◽  
Engine Model ◽  
On Line ◽  
Industrial Gas Turbine ◽  
Engine Condition

The effect of operation of compressor bleed anti-icing on the performance of an industrial gas turbine is analysed. The effect of putting this system in operation is first qualitatively discussed, while the changes on various performance parameters are derived by using a computer engine performance model. The main point of the paper is the study of the effect of anti-icing system operation on parameters used for engine condition monitoring. It is shown that operation of the anti-icing system causes an apparent modification of such parameters, which may reduce the diagnostic ability of an on-line monitoring system and produce false alarms. It is shown that by incorporating the effect of anti-icing system operation into a diagnostic engine model, such problems can be avoided and the diagnostic ability of the system is not influenced by anti-icing activation. The analysis presented is substantiated through experimental data from a twin shaft gas turbine operating in the field.

Real-Time Engine Modelling of a Three Shafts Turbofan Engine: From Sub-Idle to Max Power Rate

2006 ◽  
Author(s):  
Sogkyun Kim ◽  
Sean Ellis ◽  
Mark Challener
Keyword(s):  
Steady State ◽  
Real Time ◽  
Partial Derivative ◽  
Normal Range ◽  
The Real ◽  
Partial Derivatives ◽  
Operating Range ◽  
Engine Model ◽  
Non Linear ◽  
Perturbation Size

Real-Time Engine Models are required for operation with engine electronic control systems and/or aircraft simulators for functional demonstration. The challenge for Rolls-Royce has been to establish the sub-idle speed behaviour of the engine. This paper covers the development steps by the Civil Aerospace Modelling and Simulation team to resolve this limitation in the models. The real-time engine model is now generated using two non-linear thermodynamic engine models. One of the thermodynamic engine models, normal range, covers the idle to max power range and the other is for sub-idle operation. Previously sub-idle operation was established by extrapolation from the normal range model. However, this method limited control system development by simulation for altitude starting adding time to altitude test programmes in high cost facilities. The requirement for the technique is to obtain the partial derivatives and steady-state data for the whole operating range. For the partial derivative estimation in sub-idle region, a variable perturbation size is introduced and changed according to the different shaft speed so that the sensitivity issue of using a fixed perturbation size in this operating range is resolved. Furthermore, the partial derivative of each parameter from the non-linear models is fine tuned by comparing with the steady-state values for each parameter. The summation of the integrated partial derivatives should be same as the steady-state value of each engine parameter. If an error exists then an adjustment of each integrated partial derivative is conducted according to the relative weight of each integrated partial derivatives contribution to the whole. It is highlighted that error sharing between the integrated partial derivative parameters results in less error during the validation process. The real-time engine model is constructed in state-space modular subsystems in SIMULINK, which include an engine shaft block to generate the engine shaft speeds, and fuel block to generate a signal of engine lit, etc. The database generated by the process of partial derivatives is then used in calculation of engine’s shaft speeds, temperatures and pressures. For the test of the real-time engine model obtained in this study, simulation of engine starting from stationary is conducted. Using a starter torque as the input to the engine model, starter-assisted starting can be achieved. In addition, engine relighting in flight is also conducted. The output of the real-time engine model has been compared with flight test data for engine relight and agreement has been demonstrated.

Performance Model “Zooming” for In-Depth Component Fault Diagnosis

2010 ◽  
Author(s):  
N. Aretakis ◽  
I. Roumeliotis ◽  
K. Mathioudakis
Keyword(s):  
Fault Diagnosis ◽  
Measurement Data ◽  
Engine Performance ◽  
Main Tool ◽  
Performance Model ◽  
Diagnostic Methods ◽  
Performance Modelling ◽  
Engine Model ◽  
Path Component ◽  
Modelling Techniques

A method giving the possibility for a more detailed gas path component fault diagnosis, by exploiting the “zooming” feature of current performance modelling techniques, is presented. A diagnostic engine performance model is the main tool that points to the faulty engine component. A diagnostic component model is then used to identify the fault. The method is demonstrated on the case of compressor faults. A 1-D model based on the “stage stacking” approach is used to “zoom” into the compressors, supporting a 0-D engine model. A first level diagnosis determines the deviation of overall compressor performance parameters, while “zooming” calculations allow a localization of the faulty stages of a multistage compressor. The possibility to derive more detailed information with no additional measurement data is established, by incorporation of empirical knowledge on the type of faults that are usually encountered in practice. Although the approach is based on known individual diagnostic methods, it is demonstrated that the integrated formulation provides not only higher effectiveness but also additional fault identification capabilities.

Performance Model “Zooming” for In-Depth Component Fault Diagnosis

2010 ◽  
Vol 133 (3) ◽  
Author(s):  
N. Aretakis ◽  
I. Roumeliotis ◽  
K. Mathioudakis
Keyword(s):  
Fault Diagnosis ◽  
Measurement Data ◽  
Engine Performance ◽  
Main Tool ◽  
Performance Model ◽  
Diagnostic Methods ◽  
Engine Model ◽  
Path Component ◽  
1D Model ◽  
Compressor Performance

A method giving the possibility for a more detailed gas path component fault diagnosis by exploiting the “zooming” feature of current performance modeling techniques is presented. A diagnostic engine performance model is the main tool that points to the faulty engine component. A diagnostic component model is then used to identify the fault. The method is demonstrated on the case of compressor faults. A 1D model based on the “stage stacking” approach is used to “zoom” into the compressors, supporting a 0D engine model. A first level diagnosis determines the deviation of overall compressor performance parameters while zooming calculations allow a localization of the faulty stages of a multistage compressor. The possibility to derive more detailed information with no additional measurement data is established by the incorporation of empirical knowledge on the type of faults that are usually encountered in practice. Although the approach is based on known individual diagnostic methods, it is demonstrated that the integrated formulation provides not only higher effectiveness but also additional fault identification capabilities.

Gas Turbine Engine Performance Model Applications Using an Object-Oriented Simulation Tool

2006 ◽  
Author(s):  
A. Alexiou ◽  
K. Mathioudakis
Keyword(s):  
Engine Performance ◽  
Object Oriented ◽  
Performance Model ◽  
Simulation Tool ◽  
Performance Models ◽  
External Application ◽  
Turbine Engine ◽  
Engine Model ◽  
Turbine Component ◽  
Engine Components

Engine performance models are used throughout the life cycle of an engine from conceptual design to testing, certification and maintenance. The objective of this paper is to demonstrate the use and advantages of an engine performance model, developed using an object-oriented simulation tool, for the following applications: • Building an engine model from existing engine components and running steady state and transient calculations. • Development and integration of a new cooled turbine component in the existing engine model. • Accessing the engine model from an external application. • Using an external legacy routine in the engine model.

Development and Integration of Rain Ingestion Effects in Engine Performance Simulations

2014 ◽  
Author(s):  
I. Roumeliotis ◽  
A. Alexiou ◽  
N. Aretakis ◽  
G. Sieros ◽  
K. Mathioudakis
Keyword(s):  
Engine Performance ◽  
Velocity Slip ◽  
Droplet Surface ◽  
Performance Model ◽  
Test Case ◽  
Case Scenario ◽  
Worst Case ◽  
Engine Model ◽  
Water Ingestion ◽  
Component Models

Rain ingestion can significantly affect the performance and operability of gas turbine aero-engines. In order to study and understand rain ingestion phenomena at engine level, a performance model is required that integrates component models capable of simulating the physics of rain ingestion. The current work provides, for the first time in the open literature, information about the set-up of a mixed-fidelity engine model suitable for rain ingestion simulation and corresponding overall engine performance results. Such a model can initially support an analysis of rain ingestion during the pre-design phase of engine development. Once components and engine models are validated and calibrated versus experimental data, they can then be used to support certification tests, the extrapolation of ground test results to altitude conditions, the evaluation of control or engine hardware improvements and eventually the investigation of in-flight events. In the present paper, component models of various levels of fidelity are firstly described. These models account for the scoop effect at engine inlet, the fan effect and the effects of water presence in the operation and performance of the compressors and the combustor. Phenomena such as velocity slip between the liquid and gaseous phases, droplet break-up, droplet-surface interaction, droplet and film evaporation as well as compressor stages re-matching due to evaporation are included in the calculations. Water ingestion influences the operation of the components and their matching, so in order to simulate rain ingestion at engine level a suitable multi-fidelity engine model has been developed in the PROOSIS simulation platform. The engine model’s architecture is discussed and a generic high bypass turbofan is selected as a demonstration test case engine. The analysis of rain ingestion effects on engine performance and operability is performed for the worst case scenario, with respect to the water quantity entering the engine. The results indicate that rain ingestion has a strong negative effect on high-pressure compressor surge margin, fuel consumption and combustor efficiency, while more than half of the water entering the core is expected to remain unevaporated and reach the combustor in the form of film.

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