Development of an automated hydraulic brake control system for testing aircraft turboshaft gas turbine engines

Качанов, Петр Алексеевич; Lytviak, Oleksandr; Derevyanko, Oleksandr; Комар, С.В.

doi:10.15587/1729-4061.2019.185539

Cited by 5 publications

(6 citation statements)

References 4 publications

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“…The influence of the FTSC characteristics on inducing self-oscillations has not been studied. Paper [16] shows that when testing a turboshaft engine with a water brake, and when the engine operates on a helicopter, the controlled system is different. This difference is determined by the different load characteristics of the helicopter main rotor and water brake system.…”

Section: Literature Reviewmentioning

confidence: 99%

“…The dynamic model of the free turbine rotor is presented in detail in [16]. According to [16], the equation of rotor dynamic for the (FT + WB) system is linear and in relative variables takes the following form:…”

Section: Dynamic Model Of the Free Turbine Rotormentioning

confidence: 99%

“…For correct testing of turboshaft engines with water brake, it is necessary to provide full emulation of the characteristics of the system (helicopter main rotor) [16,17] or make corresponding adjustments to the dynamic parameters of the controller at the time of testing. Such an adjustment may be a change in the time constant of free turbine speed controller.…”

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confidence: 99%

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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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Section: Literature Reviewmentioning

confidence: 99%

Section: Dynamic Model Of the Free Turbine Rotormentioning

confidence: 99%

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

et al. 2021

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“…The authors demonstrated the possibility to ensure the stability of the system by the appropriate choice of control algorithms. Work [4] described the experimental static characteristics of FTRR in the pumps-regulators such as NR-3. It is shown that the actual characteristics of pumps-regulators such as NR-3 may have non-linear features: kinks and breaks of the first kind.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

“…The flow rate factor depends significantly on the Reynolds number [2,4]; we cannot ignore this dependence during the calculation and research.…”

Section: Literature Review and Problem Statementmentioning

confidence: 99%

Devising quality control criteria for manufacturing control valves of the type «nozzle-flap»

Lytviak¹,

Комар²,

Derevyanko³

et al. 2021

EEJET

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This paper is a continuation of research into the causes and ways to eliminate the generation of self-oscillations in the system of automatic regulation of rotations of the free turbine in the turboshaft gas turbine engines of helicopters. The study of dynamic processes in the system of automatic regulation of free turbine’s rotations in a turboshaft GTE has shown that one of the reasons for the development of self-oscillations is the poor performance of the control valve of the type «nozzle-flap» in the rotation regulator’s hydraulic drive. At a pump-regulator plant, the criterion for the quality of control valve execution or repair implies that the geometric size of the valve parts and the flow rate of working fluid through the valve when the flap is closed meet the technical requirements. As practice shows, this is not enough. With this approach, valve defects manifest themselves only during the tests of assemblies as part of the engine. This paper proposes a method to examine the characteristics of control valves such as «nozzle-flap», as well as criteria for assessing the quality of their execution. Experimental characteristics of control valves such as «nozzle-flap» for an actual regulator of free turbine rotation frequency are given. New data on the outflow of liquid from the nozzle with a flap have been obtained. It is shown that the destruction of the stagnation zone in the nozzle tip could result in that the valve flow rate increases, which negatively affects the characteristics of the hydraulic drive and regulator in general. A technique has been proposed to improve the stability of the valve’s performance by increasing the relative length of the nozzle. It is shown that the most informative characteristic of the valve is the dependence of flow rate on the position of the flap. Based on this characteristic, it is possible to determine the criteria for rejecting valves without testing them as part of the assembly

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Viewing electromagnetic scattering characteristics on air-brake of a stealth plane

Zhou,

Huang

2024

AEAT

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Purpose This study aims to learn the dynamic radar cross-section (RCS) of a deflection air brake. Design/methodology/approach The aircraft model with delta wing, V-shaped tail and blended wing body is designed, and high-precision unstructured grid technology is used to deal with the surface of air brake and fuselage. The calculation method based on multiple tracking and dynamic scattering is presented to calculate RCS. Findings The fuselage has a low scattering level, and the opening air brake will bring obvious dynamic RCS effects to itself and the whole machine. The average indicator of air brake RCS can be lower than –0.6 dBm2 under the tail azimuth, while that of forward and lateral direction is lower. The mean RCS of fuselage is obviously higher than that of air brake, while the deflected air brake and its cabin can still provide strong scattering sources at some azimuths. When the air brake is opening, the change amplitude of the aircraft forward RCS can exceed 19.81 dBm2. Practical implications This research has practical significance for the dynamic electromagnetic scattering analysis and stealth design of the air brake. Originality/value The calculation method for aircraft RCS considering air brake dynamic deflection has been established.

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Development of an automated hydraulic brake control system for testing aircraft turboshaft gas turbine engines

Cited by 5 publications

References 4 publications

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

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

Devising quality control criteria for manufacturing control valves of the type «nozzle-flap»

Viewing electromagnetic scattering characteristics on air-brake of a stealth plane

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