Determination of Serviceability Limits of a Turboshaft Engine by the Criterion of Blade Natural Frequency and Stall Margin

Dvirnyk, Yaroslav; Павленко, Д. В.; Przysowa, Radosław

doi:10.3390/aerospace6120132

Cited by 18 publications

(8 citation statements)

References 29 publications

(28 reference statements)

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“…Finally, a salient property can be observed when considering the stall margin, which is is one of the main serviceability limits of aeroengines [32]. Although these margins are clearly defined for static operating conditions, when the aeroengine undergoes harsh maneuvers, the compressor faces a fast increase in the pressure ratio with a quasi-constant mass flow [33].…”

Section: Key Advantages Of Variable Exhaust Nozzle Controlmentioning

confidence: 99%

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

Villarreal-Valderrama

Zambrano‐Robledo

Hernández-Alcantara

et al. 2021

Aerospace

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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 (LADRC) capabilities with a loop shaping controller (LSC) 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.

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Section: Key Advantages Of Variable Exhaust Nozzle Controlmentioning

confidence: 99%

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

Villarreal-Valderrama

Zambrano‐Robledo

Hernández-Alcantara

et al. 2021

Aerospace

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“…A model of a turboshaft engine based on the empirical controller characteristics is presented in [33], where the calculated dynamic parameters have a significant (up to 8%) error. The effect of erosive wear out on the compressor characteristic of the TV3-117 engine is given in [34] without taking into account the effect on the dynamic parameters of the gas generator. From the data presented in [35], it follows that failures of the measurement system can lead to the development of the self-oscillations.…”

Section: Literature Reviewmentioning

confidence: 99%

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

et al. 2021

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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.

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“…At the inlet and outlet of the compressor, the mass flow rate and temperature corresponding to the engine emergency operation were set. The the simulation results were validated according to the methodology described in Reference [68].…”

Section: Cfd Modelmentioning

confidence: 99%

Advanced Materials and Technologies for Compressor Blades of Small Turbofan Engines

2020

Self Cite

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Manufacturing costs, along with operational performance, are among the major factors determining the selection of the propulsion system for unmanned aerial vehicles (UAVs), especially for aerial targets and cruise missiles. In this paper, the design requirements and operating parameters of small turbofan engines for single-use and reusable UAVs are analysed to introduce alternative materials and technologies for manufacturing their compressor blades, such as sintered titanium, a new generation of aluminium alloys and titanium aluminides. To assess the influence of severe plastic deformation (SPD) on the hardening efficiency of the proposed materials, the alloys with the coarse-grained and submicrocrystalline structure were studied. Changes in the physical and mechanical properties of materials were taken into account. The thermodynamic analysis of the compressor was performed in a finite element analysis system (ANSYS) to determine the impact of gas pressure and temperature on the aerodynamic surfaces of compressor blades of all stages. Based on thermal and structural analysis, the stress and temperature maps on compressor blades and vanes were obtained, taking into account the physical and mechanical properties of advanced materials and technologies of their processing. The safety factors of the components were established based on the assessment of their stress-strength characteristics. Thanks to nomograms, the possibility of using the new materials in five compressor stages was confirmed in view of the permissible operating temperature and safety factor. The proposed alternative materials for compressor blades and vanes meet the design requirements of the turbofan at lower manufacturing costs.

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Determination of Serviceability Limits of a Turboshaft Engine by the Criterion of Blade Natural Frequency and Stall Margin

Cited by 18 publications

References 29 publications

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

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

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

Advanced Materials and Technologies for Compressor Blades of Small Turbofan Engines

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