Категория: Aeronautics

Justification for requirements for new trapped vortex combustors of aircraft engines

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Skorobogatov S. V.

Design and production of aircraft gas-turbine engines and their components is a high-scale and complex process. As separate branches of science develop, technological innovations are implemented and feed-back of their use is received, the design-and-production chain gets more complicated as well. On the one hand, this gives an opportunity to improve the product due to implementation of new ideas and approaches in its design, on the other hand, this brings about growth in the knowledge-intensity and increases the cost of the final product. In its turn, need for improvement of the product is required by the system of continued airworthiness with its standards improving over time as well.

Key words: combustor, aircraft gas-turbine engine, operational requirements, method of justification for requirements, airworthiness.

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Factor analysis of processes inside an aviation engine combustor as a justification basis for the nomenclature of operational requirements

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Skorobogatov S. V.

The requirements for an aircraft engine as a whole are significantly influenced by processes inside its combustor. As justification for the nomenclature of operational requirements is based on some laws of effects of different parameters, it is necessary to carry out a factor analysis of the processes inside the combustor for revealing these laws both without any heat effect on the flow kinetics and with it during fuel combustion. For this purpose, an integrated system of forming external appearance of the research object has to be built and this, in its turn, implies its fragmentation into separate locations and detailed elaboration of the combustor block-diagram piece by piece. Then the results from separate parts have to be matched and integrated into a unified system for coherent configuration of the research object and during calculations this is the system which is under the factor analysis. The factor analysis of both the intermediate and final results of optimization according to the chosen criteria allows justifying the list of operational requirements necessary for the desired level of simulations. The article presents the factor analysis of processes in the inlet of the trapped vortex combustor.

Key words: combustor, aircraft gas-turbine engine, operational requirements, justification of requirements, factor analysis.

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Test bench development for the functional hazards assesment of an integrated flight control system validation using model-based design

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Lituev N. A.

Savelev A. S.

Neretin E. S.

Integrated flight control system of a civil aircraft safety requirements validation process using means of model-based design is considered. The necessity for correct Functional Hazard Assessment is explained. Hardware and software needed for the problem are described. Complex mathematical model structure and human machine interface are provided.

Key words: model-based design, control systems, flight safety, requirements validation.

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Architecture of the on-board maintenance system using the concept of allocated IMA

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Brusnikin P. M.

Dudkin S. O.

Neretin E. S.

The paper analyzes the concepts of avionics, the principles of creating complexes of avionics equipment and existing analogues of on-board maintenance systems (OMS). The architecture of the OMS, its functional software and hardware for civil aircraft is proposed. OMS developed on the basis of integrated modular avionics (IMA) will allow you to unload the cable network of the aircraft, increase the reliability of the system as a whole, and simplify the work with OMS for the ground maintenance personnel.

Key words: civil aircraft, integrated modular avionics, on-Board Maintenance System, distributed architecture, avionics.

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Preliminary assessment of tracking the autopilot signals by the active controls on a civil aircraft

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Savel’ev A. S.

Neretin E. S.

The main purpose of civil aviation is to provide economical, reliable and safe flying. The integrated (fly-by-wire) control system and autopilot system are among the most important aircraft systems. The fly-by-wire control system includes, among other things, controls in the cockpit – yokes (Boeing) and side sticks (Airbus, Irkut, Sukhoi). The side sticks are nowadays a priority in cockpit controls development due to increase of cost-effectiveness compared to the yokes. The rigidly connected yokes provide force feedback for the pilots both in automatic and in manual control modes.   When using the side sticks the pilot has no force feedback because there are no mechanical connections. This has a negative influence on flight safety.  To solve the problem active side sticks are being developed and implemented nowadays. The active side sticks are not certified for any large civil airplanes. The aim of the paper is to give a preliminary assessment of safety of tracking the autopilot signals by the active stick in accordance with   SAE ARP 4761 and SAE ARP 4764A recommendations.

Key words: active controls, control systems, flight safety, fault tree analysis, assessment of functional hazards.

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Circulation-vortex method of activating the wing thrust over the underlying surface

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UDK 629.735.33.015 BBK 39.15

Kirenchev A. G.

Danilenko N. V.

The article deals with the issue of possible vortex activation of the working process of the wing thrust over the underlying surface. The useful effect of this working process can manifest itself in reducing the aircraft take-off and landing roll in the field of wing vortex interference with the airfield ground. The area of practical use could cover the lifting surfaces of hydrofoil crafts, ram-wing crafts and similar vehicles at low flight altitudes. The vortex activation of the wing thrust is based on the professor N.Ye.Zhukovskiy’s theorem about the wing lift and the mirror effect of the underlying surface proposed by Prandtl. The authors defined the physical and kinematic essence of interference of a linear vortex with a flat underlying surface.  The effect of that kind of vortex interference is represented due to comparison of auto-travel of vortex smoke rings having a different diameter and generated by an identical force pulse. The authors stated the fact of force interaction between a vortex ring and a hard flat wall which forms the basis of the method of vortex activation of the wing thrust capable of reducing the drag. As an object of theoretical research the linear infinitely long vortex of intensity Г = 2p  allowing the mathematical expression of Biot-Savart law to be reduced to the function of vortex velocity св = f (1/(2h)). The kinematic vortex characteristic is represented as a dependence of travel speed on the height of its position above the screen. The article identifies the main consequences of vortex and screen interference and areas of their application.

Key words: thrust, circulation of velocity Г, vortex interference, flat screen, vortex travel, vortex characteristic.

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Automation of verifying the electronic display systems of modern and advanced objects of civil aviation

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UDK 681.518.3 BBK 39.56

Mamkin E. M.

Krytsin A. V.

Ilyashenko D. M.

Dyachenko S. A.

Neretin E. S.

The authors analyzed the existing means of automation of verifying the software of aircraft onboard equipment. As the result they developed a software application which automates verifying the electronic display systems of modern and advanced civil airplanes as well as a testing technique for its use. The proposed solution allows reducing time and financial costs of system testing.

Key words: civil airplane, avionics, software, verification, image recognition, neural network.

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Architecture of the head-up display system for advanced civil airplanes

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UDK 681.518.3 BBK 39.56

Dyachenko S. A.

Chufirin V. A.

Neretin E. S.

The paper presents the analysis of design principles for avionic complexes as well as for modern systems of indication in the cockpit. The authors developed the architecture of the head-up display system for advanced civil transport airplanes based on the concept of integrated module avionics. The applied approach allows shortening the time spent for development, tests and certification of an airplane as well as reducing the cost of aircraft operation and its weight and size.   

Key words: civil airplane, integrated module avionics, information presentation systems, systems of technical imaging, head-up display.

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The assessment of positioning error characteristics of combined GLONASS/GPS receivers

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UDK 621.391:621.396 BBK 39.57-5 S66

Skrypnik O. N.

Arefyev R. O.

Arefyeva (Astrakhanceva) N. G.

The Global Navigation Satellite Systems `(GNSS) such as GLONASS (Russia) and GPS (the USA) systems find wide application in different fields including aviation. The growing demands of different users’ groups for accuracy and reliability of positioning can be met by solving a navigational problem with the use of all visible satellites which belong to different systems. This function was implemented in combined GNSS receivers, the research of performance features and positioning error characteristics of combined GLONASS/GPS receivers under different conditions of use and in different operational modes being relevant. The paper contains the results of natural experiments for investigation of positioning accuracy characteristics carried out with Geos-1M receiver. The experiments were performed in urban settings and in open terrain, in GLONASS and GPS operation modes of the receiver as well as in GLONASS/GPS combined mode. The experimental results were analyzed with the help of special software and algorithms of statistical manipulation. The obtained results allow assessing the main statistical characteristics of positioning errors and operational efficiency of the combined GNSS receiver under different conditions and in different operational modes. It can be used in practice for selecting a more efficient operational mode of the combined receiver for given conditions as well as for validating mathematical models of the positioning errors of SNS receivers.

Keywords: global navigation satellite system, GNSS, combined GNSS receiver, positioning accuracy.

*This work was supported by the Russian Foundation for Basic Research (Grant No. 19-08-00010 A).

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Technology of manufacturing some elements of a combustion chamber with a lateral system of reverse current area formation

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UDK 621.45.022 BBK 39.55

Skorobogatov S. V.

Isaev A. I.

With each passing year, the operational requirements for the aircraft power plants are getting stricter and stricter. The combustion chamber as one of the main parts of an aircraft engine determines the indicators of its efficiency, reliability and environmental compatibility. The indicators can be improved due to taking into account the operational requirements at the stage of designing a combustion chamber.

As the concept of a combustion chamber with a lateral system of reverse current area formation implies presence of a number of thin-walled elements as well as double-curved surfaces, designing a chamber of such construction is a complex engineering problem.

The article describes a technology of manufacturing a combustion chamber of the desired design on an example of experimental model for a chamber stand.

Key words: combustion chamber, aircraft gas-turbine engine, operational features, technology of manufacturing, combustion process.

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