Aerospace

Editorial

Jump to: Research

2 pages, 161 KiB

Open AccessEditorial

Special Issue “Technologies for Future Distributed Engine Control Systems”

by Radoslaw Przysowa

Aerospace 2021, 8(12), 379; https://doi.org/10.3390/aerospace8120379 - 6 Dec 2021

Viewed by 1973

Abstract

Current trends in aviation greatly expand the use of highly integrated, increasingly autonomous air vehicles, with distributed engine control systems (DECS) [...] Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

Research

Jump to: Editorial

13 pages, 541 KiB

Open AccessArticle

Comparative Study of a Powerplant Life Consumption Rate When Installed in Two Different Aircraft Variants

by Ioannis Templalexis, Ioannis Lionis and Nikolaos Christou

Aerospace 2021, 8(11), 327; https://doi.org/10.3390/aerospace8110327 - 2 Nov 2021

Cited by 4 | Viewed by 2200

Abstract

The Hellenic Air Force (HAF) operates both EMB-145 and EMB-135 LR versions of Embraer aircraft, used in surveillance and civil missions respectively. These aircraft are equipped with the same version of Rolls Royce, AE 3007 turbofan engine. This study aims to quantify and [...] Read more.

The Hellenic Air Force (HAF) operates both EMB-145 and EMB-135 LR versions of Embraer aircraft, used in surveillance and civil missions respectively. These aircraft are equipped with the same version of Rolls Royce, AE 3007 turbofan engine. This study aims to quantify and compare the life consumption rate of this engine when installed in each of the two aircraft variants. Two typical missions, one for each variant, were constructed based on mission profile data dictated by the aircraft commanders. For each mission profile segment, corresponding engine data were matched out of the engine recordings archives held by the Hellenic Air Force. The life consumption rate was based on the Low Cycle Fatigue (LCF) and creep cumulative detrimental effect on the rotor blades of the 1st High-Pressure Turbine stage. For the LCF, the rainflow method was used to determine the respective loading cycles, whereas the Larson - Miller parameter method was used to determine the consumed life fractions due to creep. The main conclusion of the study was that the engine when installed in the EMB-145 military variant, is much more loaded. Despite the fact absolute life consumption values could hide a great level of uncertainty, the comparative outcomes wherein errors are, to a certain extent, cancelled out, could be used as a rule of thumb when monitoring engine life consumption rates. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures

Figure 1

14 pages, 7736 KiB

Open AccessCommunication

Architecture of Distributed Control System for Gearbox-Free More Electric Turbofan Engine

by Viktor Popov, Sergiy Yepifanov, Yevhenii Kononykhyn and Aleksandr Tsaglov

Aerospace 2021, 8(11), 316; https://doi.org/10.3390/aerospace8110316 - 24 Oct 2021

Cited by 9 | Viewed by 3397

Abstract

This article presents the development of the electric turbofan engine in distributed architecture with a design thrust in the range of 3 to 7.5 and from 7.5 to 30 kN for small and medium-sized unmanned aerial vehicles. The engine subsystems are considered as [...] Read more.

This article presents the development of the electric turbofan engine in distributed architecture with a design thrust in the range of 3 to 7.5 and from 7.5 to 30 kN for small and medium-sized unmanned aerial vehicles. The engine subsystems are considered as separate smart modules with a built-in control system, exchanging data via a digital channel with the central engine control and diagnostics unit. The key smart engine units are combined in the following subsystems: starter and turbine generators, oil pumps, actuator of guide vanes, fuel pumps, fuel metering unit, control and diagnostic unit. All pumps and guide vane actuator are electrically driven. Control and monitoring signals are transmitted via a digital bus. Functional and reliability analysis and the technical configuration design of each subsystem are presented. Based on analysis of the architecture of distributed control systems for a gearbox-free electric engine, different configurations of described subsystems are proposed. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures

Figure 1

21 pages, 2107 KiB

Open AccessArticle

Turbojet Thrust Augmentation through a Variable Exhaust Nozzle with Active Disturbance Rejection Control

by Francisco Villarreal-Valderrama, Patricia Zambrano-Robledo, Diana Hernandez-Alcantara and Luis Amezquita-Brooks

Aerospace 2021, 8(10), 293; https://doi.org/10.3390/aerospace8100293 - 11 Oct 2021

Cited by 3 | Viewed by 3609

Abstract

Turbojets require variable exhaust nozzles to fit high-demanding applications; however, few reports on nozzle control are available. The purpose of this paper is to investigate the possible advantages of an exhaust gas control through a variable exhaust nozzle. The control design method combines [...] Read more.

Turbojets require variable exhaust nozzles to fit high-demanding applications; however, few reports on nozzle control are available. The purpose of this paper is to investigate the possible advantages of an exhaust gas control through a variable exhaust nozzle. The control design method combines successful linear active disturbance rejection control (

L A D R C

) capabilities with a loop shaping controller (

L S C

) to: (i) allow designing the closed-loop characteristics in terms of gain margin, phase margin and bandwidth, and (ii) increase the LSC disturbance rejection capabilities with an extended state observer. A representation of the nozzle dynamics is obtained from first principles and adapted to achieve a stream-velocity-based control loop. The results show that the resulting controller allows improving the expansion of the exhaust gas to the ambient pressure for the whole operating range of the turbojet, increasing the estimated thrust by 14.23% during the tests with experimental data. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures

Figure 1

16 pages, 6557 KiB

Open AccessArticle

Clocking and Potential Effects in Combustor–Turbine Stator Interactions

by Pawel Flaszynski, Michal Piotrowicz and Tommaso Bacci

Aerospace 2021, 8(10), 285; https://doi.org/10.3390/aerospace8100285 - 2 Oct 2021

Cited by 3 | Viewed by 2090

Abstract

Investigations of combustors and turbines separately have been carried out for years by research institutes and aircraft engine companies, but there are still many questions about the interaction effect. In this paper, a prediction of a turbine stator’s potential effect on flow in [...] Read more.

Investigations of combustors and turbines separately have been carried out for years by research institutes and aircraft engine companies, but there are still many questions about the interaction effect. In this paper, a prediction of a turbine stator’s potential effect on flow in a combustor and the clocking effect on temperature distribution in a nozzle guide vane are discussed. Numerical simulation results for the combustor simulator and the nozzle guide vane (NGV) of the first turbine stage are presented. The geometry and flow conditions were defined according to measurements carried out on a test section within the framework of the EU FACTOR (full aerothermal combustor–turbine interactions research) project. The numerical model was validated by a comparison of results against experimental data in the plane at a combustor outlet. Two turbulence models were employed: the Spalart–Allmaras and Explicit Algebraic Reynolds Stress models. It was shown that the NGV potential effect on flow distribution at the combustor–turbine interface located at 42.5% of the axial chord is weak. The clocking effect due to the azimuthal position of guide vanes downstream of the swirlers strongly affects the temperature and flow conditions in a stator cascade. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures

Figure 1

15 pages, 2175 KiB

Open AccessArticle

High Temperature Magnetic Sensors for the Hot Section of Aeroengines

by Edward Rokicki, Radoslaw Przysowa, Jerzy Kotkowski and Paweł Majewski

Aerospace 2021, 8(9), 261; https://doi.org/10.3390/aerospace8090261 - 13 Sep 2021

Cited by 10 | Viewed by 3308

Abstract

Magnetic sensors are widely used in aeroengines and their health management systems, but they are rarely installed in the engine hot section due to the loss of magnetic properties by permanent magnets with increasing temperature. The paper presents and verifies models and design [...] Read more.

Magnetic sensors are widely used in aeroengines and their health management systems, but they are rarely installed in the engine hot section due to the loss of magnetic properties by permanent magnets with increasing temperature. The paper presents and verifies models and design solutions aimed at improving the performance of an inductive sensor for measuring the motion of blades operated at elevated temperatures (200–1000 °C) in high pressure compressors and turbines. The interaction of blades with the sensor was studied. A prototype of the sensor was made, and its tests were carried out on the RK-4 rotor rig for the speed of 7000 rpm, in which the temperature of the sensor head was gradually increased to 1100 °C. The sensor signal level was compared to that of an identical sensor operating at room temperature. The heated sensor works continuously producing the output signal whose level does not change significantly. Moreover, a set of six probes passed an initial engine test in an SO-3 turbojet. It was confirmed that the proposed design of the inductive sensor is suitable for blade health monitoring (BHM) of the last stages of compressors and gas turbines operating below 1000 °C, even without a dedicated cooling system. In real-engine applications, sensor performance will depend on how the sensor is installed and the available heat dissipation capability. The presented technology extends the operating temperature of permanent magnets and is not specific for blade vibration but can be adapted to other magnetic measurements in the hot section of the aircraft engine. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures

Figure 1

19 pages, 10503 KiB

Open AccessArticle

Neural Nonlinear Autoregressive Model with Exogenous Input (NARX) for Turboshaft Aeroengine Fuel Control Unit Model

by Maria Grazia De Giorgi, Luciano Strafella and Antonio Ficarella

Aerospace 2021, 8(8), 206; https://doi.org/10.3390/aerospace8080206 - 29 Jul 2021

Cited by 14 | Viewed by 3129

Abstract

One of the most important parts of a turboshaft engine, which has a direct impact on the performance of the engine and, as a result, on the performance of the propulsion system, is the engine fuel control system. The traditional engine control system [...] Read more.

One of the most important parts of a turboshaft engine, which has a direct impact on the performance of the engine and, as a result, on the performance of the propulsion system, is the engine fuel control system. The traditional engine control system is a sensor-based control method, which uses measurable parameters to control engine performance. In this context, engine component degradation leads to a change in the relationship between the measurable parameters and the engine performance parameters, and thus an increase of control errors. In this work, a nonlinear model predictive control method for turboshaft direct fuel control is implemented to improve engine response ability also in presence of degraded conditions. The control objective of the proposed model is the prediction of the specific fuel consumption directly instead of the measurable parameters. In this way is possible decentralize controller functions and realize an intelligent engine with the development of a distributed control system. Artificial Neural Networks (ANN) are widely used as data-driven models for modelling of complex systems such as aeroengine performance. In this paper, two Nonlinear Autoregressive Neural Networks have been trained to predict the specific fuel consumption for several transient flight maneuvers. The data used for the ANN predictions have been estimated through the Gas Turbine Simulation Program. In particular the first ANN predicts the state variables based on flight conditions and the second one predicts the performance parameter based on the previous predicted variables. The results show a good approximation of the studied variables also in degraded conditions. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures

Figure 1

16 pages, 3458 KiB

Open AccessArticle

Self-Oscillations of The Free Turbine Speed in Testing Turboshaft Engine with Hydraulic Dynamometer

by Oleksandr Lytviak, Vasyl Loginov, Sergii Komar and Yevhen Martseniuk

Aerospace 2021, 8(4), 114; https://doi.org/10.3390/aerospace8040114 - 17 Apr 2021

Cited by 1 | Viewed by 2353

Abstract

Self-oscillations are one of the common problems in the complex automatic system, that can occur due to the features of the workflow and the design of the governor. The development of digital control systems has made it possible to damp self-oscillations by applying [...] Read more.

Self-oscillations are one of the common problems in the complex automatic system, that can occur due to the features of the workflow and the design of the governor. The development of digital control systems has made it possible to damp self-oscillations by applying complex control laws. However, for hydromechanical systems, such way is unacceptable due to the design complexity and the governor cost. The objective of this work is to determine the parameters of the hydromechanical free turbine speed controller, ensuring the absence of self-oscillations during ground tests of the turboshaft engine with a hydraulic dynamometer. The TV3-117VM engine (Ukraine) with the NR-3VM regulator pump (Ukraine) was selected as the object of the study. However, self-oscillations can also occur in any modifications of the TV3-117 engine with any NR-3 regulator pump. The results of the research may be of interest to engineers and scientists who investigate the dynamics of automatic control systems for similar engines. The paper analyses the nonlinear features of the empirical characteristics of the FTSC leading to self-oscillations of the engine speed. The authors propose the mathematical model of the automatic control system dynamics, which takes into account all the features of the engine and regulator pump. It is shown that the load characteristics of the water brake and the helicopter main rotor can differ significantly. Research of the dynamic characteristics of the TV3-117VM engine was carried out. The analysis showed a good agreement between the calculation results and the field test results, and made it possible to determine the parameters of the controller, which lead to self-oscillations during test. Two cases are considered. The first case includes ground tests of the engine with a water brake; the second case—flight tests of the engine as part of the helicopter’s power plant. The data obtained make it possible to develop recommendations for adjusting the hydromechanical governor without testing it on the engine. Full article

(This article belongs to the Special Issue Technologies for Future Distributed Engine Control Systems)

► Show Figures