Methods and tutorials
The formation of the educational system of the third millenium is under the scrutiny of the United Nations andin accordance with the adopted decisions therea new world educational model should become a universal mechanism to ensure the strategy of sustainable development of mankind.Education as the most important subsystem, providing stability to the whole world socio-ecological-economic system in the future, is the focus of this article.
The problem of transformation of the global educational system in response to the challenges of globalization and moved threat of antropologiekological catastrophe requires the selection and approval of new ideological and value attitude inside the existing educational system, support to which will make it possible to accomplish a passage to the most optimum civilizational development. Despite ongoing efforts in the introduction of courses sustainable development of all countries of the Bologna process and in educational institutions of the USA and Canada, the emerging system of education for sustainable development, based more on the idea of its ecologization not give the desired result.
For the permission of the prevailing situation, in the article it is proposed to turn to the traditions of the domestic thought, which was called name «Russian kosmizm». In the framework of kosmism gets new meaning the strategy of sustainable development as its basic principles are difficult to implement without the implementation of the key ideas of this conception, such as noosferizatsiya of public consciousness V.I. Vernadskogo or the idea of K. E. Tsiolkovskiy about the mastery of deep space for purposes of the solution of the problems of the overpopulation of the Earth and limitedness of natural and energy planet resources. Russian kosmists who stood at the origins of space science, and not only reflected in their works the fundamentals of cosmic world outlook, but also theoretically substantiated the transition to the humanistic-noosphere to the future of mankind. In connection with this contributors it is proposed to supplement the concept of the ecological education for purposes of sustainable development by the ideas of the «space program educational system».
Theoretical substantiation of the space program spinoffof modern education, proposed by the authors of the article provides a new look on the problem of realization of provisions of the strategy of sustainable development, strengthen the international education system to ensure sustainability of global socio-ecological-economic system in the future.
The separate theoretical positions represented in the article can be used for the development of strategy of educational establishment for the realization of the purposes of sustainable development in accordance with the recommendations of United Nations and UNESKO.
Keywords: sustainable development strategy, education for the sustainable development, crisis of world educational system, Russian kosmizm, space program of education
Mathematics. Physics. Mechanics
The study was perform to examine the dynamic response of an airplane and its payload during takeoff and landing accidents, such as collisions with a plane wall, a runway or a ground. The initial conditions for the numerical simulation of airframe dynamics problem correspond with real accidents conditions for the considered aircraft’s type.
A modeling of the structural dynamics of aircrafts under impact loads is a quite difficult problem even in simplified problem statement, so that only numerical simulation can be efficient. To solve these problems of computational mechanics the explicit algorithms are most useful. Here the finite element software LS-DYNA is used to simulate the nonlinear transient dynamic response of airframe structures. The structural elements of the airplane’s fuselage and center wing section was modeled as resultant beams with concentrated masses at the location of nonstructural units such as fuel tanks, avionics, etc. External payloads on central and two lateral hardpoints were modeled as the beams with the stiffness and the density being constant per length. The appropriate initial conditions and properties of obstacles (structural walls, runways or ground) have been considered.
The total accelerations time dependencies were obtained for both of airframe and payload. The peak acceleration of payload were calculated for each case. The strength of payload’s suspension points was estimated.
The analysis of the structural dynamics of aircrafts during different accidents is very important to estimate the impact effect to the crew, payload, some structural elements, and avionics. The risk of triggering explosive and flammable onboard items can be also estimated.
Keywords: airplane, accident, finite element method, beam, dynamic response, acceleration, impact, airframe, damping, bilinear material model
The problem to be considered in this paper isboundary problemsdevoted toa stress-deformed state of a circle cylindrical shell with varied conditions on the boundaries and with the presence of hydraulic-statics pressure action, which is constant along of an axis, that correspondents to a horizontal position of vessels, which are partially filled by a liquid. Such problem in condition of endshinge joints was solved in the V.Z. Vlasov’s monograph with the help of double trigonometric seriesmethod, in which an axial stress is shown only on the basis of the semi-momentless theory.
Since the dry part of the vessels cylindrical shell with no liquid can havethe very high temperature, which can lead to appearance of high thermo-elastic stresses, it is needed to consider a problem of stress-deformed state calculation of cylindrical shells being under action of temperature, which is constant by length and piece – constant along the contour.
The method of asymptotic synthesis (MAS) and ordinary trigonometric series with the method of initial parameters are used for an essential widening of studyingpossibilities for stress-deformed state. An attraction of the MAS is stipulated by necessity to calculate the bending moments in a zone with absence of hinge joints, for example, on the rigidly fixed edges of the shells, where it is impossible to find the bending moments on the basis of the semi-momentless theory, because of algebraic non-differential dependence between the axial and cross bending moments and the radial displacement, as far as the partial derivative of the radial displacement with respect to an axial coordinate is equal to zero; but the radial displacement is equal to zero with the condition of rigidly fixed edges of shells, therefore the bending moments are equal to zero too. But by attracting the MAS the stress-deformed state on the basis of semi-momentless theory equations was supplemented with symmetrical and unsymmetrical edge effects, destined to play an essential role in calculation of stress state on shells rigidly fixed edges.
In this way the submitted here investigations could be interpreted as some generalization of V.Z. Vlasov’s problem in the case of shells witharbitrary boundary conditions under action of both the unsymmetrical hydraulic-statics pressure and piece-constant temperature field.
The MAS in the form of differential equations of the semi-momentless theory and the edge effect theory equations allowed to get the analytical solutions and simple formulae for important unknown quantities of stress-deformed state in the case of circle cylindrical shells with varied conditions on boundaries.
Keywords: cylindrical shell, hydraulic-statics pressure, vessel, main stress tate, edge effect, temperature
The article is concerned with numerical schemes for gas-dynamics problems.
The goal of research was to develop effective numerical algorithms using conservative characteristic form of conservation laws.
Conservative characteristic form was established from divergence form of conservation laws with the aid of identity flows transformation. No linearization of the flow’s vector-function (which requires continuity of the function) was made as opposed to Euler equations. That’s why final equations are conservative and also admit discontinuous solutions. Quasi-linear conservative representation of conservation laws allows developing conservative characteristic numerical schemes and formulating necessary and sufficient conditions of stability and monotonicity.
There were made two numerical schemes which are presented in this article. First one is appropriate for one-dimensional non-static problems. A number of tests (propagation of a shock-wave through high and low density area) were made. The results appeared to be extremely accurate next to discontinuities. Shock-wave and tangential discontinuity fronts are propagated without numerical diffusion influence. Two-dimensional supersonic and hypersonic flows modeling are first extension of the method. The fact that fluid velocity is greater than sound velocity allows us to solve time-independent equations. Static computations of supersonic flow in a flat duct with a wedge were made. The scheme can be simply modified to solve cylindrical-cemetery problems.
Numerical schemes for three-dimensional models call for further investigations. Present study demonstrates wide range of advantages which conservative form of conservation laws provides for construction of numerical schemes for gas dynamics. Monotonicity, stability, conservative and characteristic type make them work for discontinuous flows modeling and accounts for high-precisely results.
Keywords: conservative characteristic scheme, shock-capturing, static supersonic flows, necessary and sufficient condition of stability and monotonicity
The objective of present paper is the method for computation of the location coordinates of GLONASS and GPS navigation satellites according to received ephemeris data and reasoning for the delays of gravitational interaction and electromagnetic signal being delivered from a satellite. Approach proposed in the paper is named the theory of a signal delay; it is based on the proper computation of the delays of signals and their derivatives. It was shown that the analogue of the electromagnetic signal delay proves to be a clock shift in one inertial coordinate system relative to another one – such data are stated in a special theory of relativity. When the radial range computed at the start moment of the gravitational interaction signal radiation, then the time delay could be interpreted as unaccounted time interval resulting in a calculation of the coordinates with errors based on the differential expression application.
The intermediate results are the expressions to calculate the radial range during the signal radiation time interval as well as this interval to be computed. The expressions obtained are practically identical to the Lorentz transform as to coordinate and time in the case of small radial rates of the signal sources compared with the velocity of light. The results obtained are invoked to specify the calculations are related to the GLONASS and GPS coordinates computations and currently based on application of the general and special theories of relativity.
The theory of a signal delay is predicated on the classical representation of space and time and makes it possible to take into account the relativistic and gravitational effects and to explain them from the physically intelligible event – signals delay in the air.
Keywords: theory of delay of the signals, special theory of a relativity, GLONASS and GPS
The use of parametric geometrical models for aviation constructions design is investigated. The parameterization of geometrical models is considered for groups of constructively and geometrically similar details containing the curvilinear surfaces of aircraft theoretical contour. The parametric model of such detail allows one to construct the models of remaining details by use of the simple change of required parameters and will reduce the input data for digital models of the considered group’s details in direct ratio to number of details.
The geometrical element of auxiliary geometry forming the sized basis for geometrical model of a detail is called a "binding". To secure full model’s parameterization and to eliminate geometry failures the determination of the bindings must be independent from the model position so that allows one to conserve all geometrical reconstructions at ever change of the position. This specificity requires avoiding the bindings’ changeover if the model position in construction changes.
To eliminate the mentioned changeover of binding planes and surfaces the continuous determination of axial elements used as bindings is necessary instead of the discrete one. The use of the revealed regularities of determination of axes of the constructive and force diagram (CFD) is proposed as a continuous determination method. This approach is based on the known fact that the discretely located axes can be defined by parallel shift with a certain step with respect to its initial position. The use as bindings of the elements forming the sized bases for CFD axes is proposed contrary to the use of the force set axes. The term "basic bindings" is for this kind of bindings introduced.
On the basis of the described approach and the use of available basic bindings the remaining bindings can be determined “in model” instead of their import from the master geometry. Such bindings’ determination avoids their changeover at ever change of the model position and requires only the new values of parameters defining the binding’s position with respect to the rather basic bindings. The proposed above bindings’ determination avoids also failures of evolution of geometrical elements at changes of model’s position in aggregate construction. On the other hand the model spatial position of the model can be parameterized together with the model’s form.
A new method of construction of parametric models for aviation constructions that takes into account the multiplication on theoretical contours can be developed on the basis of the proposed continuous bindings’ determination aproach.
Keywords: aviation designs, theoretical contour, parametrical model
The Environmental Control Systems (ECS) of most modern aircraft include High-Pressure Water Separation (HPWS) loop schemes. Fig. 1 shows a typical layout of such HPWS loop scheme.
Fig. 1. Layout of a loop scheme of high-pressure water separation.
where C, R are the heat exchangers (C is the condenser, R is the reheater); Т1, Т2 are the first and second cooling stages of multi-stage turbo-machine; MS-1, MS-2 are the moisture separators (dryer dehumidifiers).
The functioning of HPWS loop scheme during humid air processing influences the dependence of its workability on the altitude and speed of the airplane flight as well as the operability of separate ECS units. Thus the purpose of this paper is to calculate ECS workability areas for various values of altitude and speed of flight. The calculation is performed by using the available mathematical model of HPWS loop scheme and the computing program that is based on this model. The paper also aims at considering possibilities of the system optimization in terms of starting and equivalent weight criteria.
The mathematical model of the considered system includes the general equation of humid air enthalpy as well as a system of the equations, which are used for calculation of air parameters at the each unit outlet.
The equations were solved by using the modified method of chords, which was developed with taking into account the function features connected with the processes of moisture evaporation and freezing.
The developed program was used to obtain the workability areas depending on the altitude and speed of flight.
A method of evaluation of operability of separate ECS units was developed and applied to analyze system functioning in the course of the numerical experiment. This method includes tests and criteria for each unit.
Various ECS were compared according to the criteria of starting and equivalent weight with the help of the developed program. This calculation was performed for several versions of the system structure.
The conducted research showed that the workability area of ECS with the HPWS loop scheme is narrow when humidity has no profound effect on system units functioning (Fig. 2),
Fig. 2. ECS workability areas depending on altitude and speed of flight.
where number “1” is the area for the air cycle ECS with one-stage cooling turbine without the HPWS loop scheme; number “2” is the area for the ECS with the HPWS loop scheme, which includes a condenser, a reheater and a one-stage cooling turbine; number “3” is the area for the ECS with the HPWS loop scheme, which includes a two-stage cooling turbine.
However the HPWS loop scheme starts to gain an advantage upon the transition of the system outlet air temperature to negative values at low flight altitudes. This advantage emerges due to the reduction of the required conditioning air consumption for the HPWS loop scheme. The systems without the HPWS loop scheme are forcedly limited to positive values of the output temperature for all flight modes.
The results of the performed calculations are adduced in Fig. 3. Fig. 3 shows that there is a strong correlation between the adjusting weight of the system and its starting weight.
Fig. 3. The starting and equivalent weight of the considered ECS types.
where type #1 is the air cycle ECS with one-stage cooling turbine without the HPWS loop scheme; type #2 is the ECS with the HPWS loop scheme, which includes only a condenser; type #3 is the ECS with the HPWS loop scheme, which includes a condenser and a reheater; type #4 is the ECS with the HPWS loop scheme, which includes a two-stage cooling turbine.
Fig. 4 presents the calculated areas of system operability as well as the dependence of the total weight of the condenser and reheater on their efficiencies (hc and hR).
Fig. 4. Dependence of the total weight of the condenser and reheater on their efficiencies hc and hR.
The analysis allowed to establish the following: to optimize ECS with HPWS loop scheme in terms of the weight criteria it is desirable to have the values of condenser and reheater efficiencies close to each other.
During the research an assumption was made that the air-flow rate does not change within the allocated ECS section and system functioning mode is considered to be stationary.
The usage of the HPWS loop scheme as a part of the ECS narrows its workability area. Therefore, it is expedient to provide the ECS with bypass lines. These lines would allow the system to go around some of the units of the loop scheme during the flight at the altitudes, at which the amount of moisture in the atmospheric air is insignificant.
The comparative calculations showed that the system with HPWS loop scheme, which includes a condenser and a reheater, is optimum with respect to the criteria of starting and equivalent weight. Usage of the loop scheme with the two-stage cooling turbine can be justified by the increase of operation reliability of the heat exchangers.
Application of the proposed numerical methods for modeling of aviation ECS functioning at the early design stage can undoubtedly be useful and serve a practical purpose for organizations connected with manufacturing and operation of these systems.
Keywords: humid air, high-pressure water separation loop sheme, heat exchanger, environment control system, workability area, installed mass, starting and equivalent weight criteria
The subject of research in the proposed article is a method of accuracy evaluation for helicopter target sight system.
The topic of the paper is the application of analytical method of helicopter target sight system pointing accuracy evaluation.
The aim of the article is improvement of helicopter target sight system by means of aiming mark displaying accuracy and comparison the analytical evaluation method with the results of mathematical simulation.
The methods of mathematical simulation were used.
The article presents analytical evaluation method of helicopter target sight system by using aiming mark displaying accuracy, involving initial measurers and pseudo-measures. The method is compared with mathematic model approach. It is concluded that the evaluation results, received by using both methods are closed, but the method, described in the article, allows the user to calculate percentage of primary data error in resulting error. The analytical method, presented in the article, can be used for solution the problem of aiming in the presence of pseudo-measures. Variants of practical use of offered method are also given in the article.
The paper results show that the developed analytical method useful for better description the evaluation of helicopter target sight system by means aiming mark angular data assessment accuracy. Also the percentages of primary errors assessed with analytical method are reliable.
There are several conclusions can be drawn from the paper. Firstly, the use of analytical method in the design of helicopter target sight system allows defining the requirement of source information sensor and its processing algorithms. Secondly, this method helps to detect and apply critical aiming conditions. Thirdly, the mathematical method indentify the reference quantity factor in algorithm of aiming mark in helicopter target sight system for different application conditions.
Keywords: target sight system, accuracy, analytical method, pseudo-measures, aiming mark, percentage
The main subject of this study is an interplanetary trajectory of spacecrafts with electric propulsion. The paper is devoted to the optimization of the spacecraft trajectory with electric propulsion into working heliocentric orbit. The purpose of this article is the analysis of the optimal directinsertion trajectory of the spacecraft with electric propulsion into the working heliocentric orbit with low perihelionand high inclination as well as the analysis of the possible types of extremals.
The trajectory optimization problem of spacecraft with electric propulsion into working heliocentric orbit with a given perihelion radius, a phelionradius and inclination to the ecliptic plane for the fixed time is carried out by usingthe Pontryagin’s maximum principle. The compliance with the transversality conditions for solving the boundary value problem was ensured.
The analysis of the possible types of extremals of the optimal directinsertion trajectories of the spacecraft with electric propulsion into the working heliocentric orbit with low perihelionand high inclination was carried out. As a result of this work the characteristics ofthe optimal direct insertion trajectory of the spacecraft into the target heliocentric orbit for space transportation system on the basis ofthe launch vehicle "Soyuz-2," the chemical upper stage "Fregat" and the electric propulsion type “RIT 22” are obtained. The analysis of multiple types of extremals is presented. Seven types of extremals are shown and their propertiesare analyzed.
These results can be used during the development of space research programs with using the heliocentric trajectories. For example, to study the inner heliosphere of the Sun from close distances and positions of outer ecliptic plane.
By using the space transportation system based on the launch vehicle "Soyuz-2," the chemical upper stage "Fregat" and the electric propulsion system type «RIT-22", we can insert the spacecraft with the mass more than1350 kg into the heliocentric orbit with a low perihelion and inclination to the ecliptic plane equal to 30 degrees. In this case, the required mass of xenonis 640...650 kg.
The essential optimal conditions for spacecraft insertion into the heliocentric orbit are obtained and ensuring compliance with these conditions in the solution of the boundary value problem are carried out.
Keywords: spacecraft, optimal trajectory, Sun exploration, Pontryagin’s maximum principle, transversality conditions, ion thrusters
This article provides the methodology and gives the performances analysis of launch vehicle modification based on the ballistic missiles, in which the additional upper fourth stage with a solid engine is used.
The given parameters of ballistic missiles, which are used in launch rocket base, observe the problem of fourth stage rational parameters choice and the program for elimination of transport operation, as well as provide the delivery of maximum payload mass into the desired orbit.
The fourth stage includes the solid propellant motor with control system and connectors compartments, the reserve of the fourth stage fuel and payload which includes the aggregate and instrument compartment with the control system.
Research method is built in such way that the use of the fourth stage mass m04 = mпг + mРБ4 = m04зад with given breeding program determines the altitude and speed of aircraft at the point of apogee — Va. In order to provide the necessary aircraft movement on the orbit ΔV = Vобр — Va the essential addition to the speed was calculated. We suggest that the total impulse thrust of fourth stage will be given directly in the point of contact within a negligible amount of time.
Using the dependence DV = — Pуд4ЧgЧn(1-mт4),
It is possible to calculate payload delivered to orbit mПГ = m04 — mРБ4.
The method allows to predict the characteristics of launch vehicle modification based on ballistic missiles. The achievable performance of launch vehicle modification by payload mass and circular orbit altitude are determined with the help of design features in orbital injection (apogee motor start of the fourth stage) and given parameters of the upper fourth stage with a solid propellant motor.
It is necessary to underline that the maximum of relative mass payload of launch vehicle modification (it is measure of effectiveness of launch vehicle modification) is achieved when m04 is equal to 900 kg. In this case the apogee altitude ha is equal to 800 km and the mass payload delivered to orbit mпг is equal to 160 kg. At the same time the maximum mass delivered to orbit will be obtained when m04 will be equal to 2600 kg (mпг is 270 kg). In this case the orbit altitude is 300 km. The resulting estimates can be used for direction choice of the project design in design bureau.
Keywords: upper fourth stage, modification, payload, algorithm, height of the orbit, problem, parameters
This paper presents the authors pilot project of the collective of authors about habitability of manned lunar station, problems and methods of its solution.
Lunar base will be an extremely productive choice for future space efforts. Further exploration of the Moon is scientifically important; the Moon offers a stable and radio-quiet platform for astronomy and space physics, material resources are available for use in near-Earth space or on the Moon itself, the Earth-Moon operations offer the technological stimulus for interplanetary missions at lower cost with less risk. We face new standards of the Moon Base habitability and construction. It is the task with many unknowns.
From detailed investigation of the habitability problem we understand to all stages of so unique design. Case study of the habitability showed the next:
Summing up this report, it is worthy to note that only wrikle on substandard problem of manned lunar base will afford to formulate creations and costing methods relating to all stages of so unique design.
- there is exist general reasonably sufficient understanding challenges on problem of habitability of the lunar base;
- basic problem issues of lunar base habitability are not yet form to stage of disclosure of design objectives of the lunar base;
- Alongside with preceding subject soundly was proven that LSS half-closed type. Basis of reclamation subsystems becomes the biological link of LSS with including in it the most secure physical and chemical LSS;
Keywords: safety, life quality, lunar station habitability, life support system (LSS), medical control, exobiology
Aerospace propulsion engineering
A new approach to solving the problem of pulsed detonation engines has been proposed. The approach differs complete absence of mechanical valves and special ignition systems. The pulsation process in such an engine is initiated by generating high-frequency self-oscillations in a gas-dynamic resonator. The resonator is periodically filled with a specially prepared, nonequilibrium, exothermically reacting fuel-air mixture. The heat enhancing the oscillation amplitude is released in the course of detonation-like combustion. The results of model experiments are reported.
For present day possibility of the further improvement of the features aircraft gas-turbine engines is practically exhausted that is explained by restriction on existing materials, used at production GTE and many other reasons.
Opened at the last years perspective of the using two-stage combustion fuel have greatly raised the interest to engines of periodic fuel combustion.
In the article the perspective model of the engine with two-stage combustion fuel is described. The advantage and defects of the different schemes of the engines, similar models and problems of the designing are considered.
Transition from the thermodynamic cycle with heat emission under the constant pressure (p — const) to the cycle with heat emission under the constant volume (v — const) is one of possible ways to improve the efficiency of aircraft engines. Theoretical studies have proved that this would result in achieving the increase of the cycle efficiency by the factor of 1.3 to 1.5. For several decades, the attempts were made to implement the theory of the pulsed engines (based on the v = const concept) into practice, but they did not succeed so far. This is attributed to the complexity of the design, inertia and low passing capability of mechanical valves in these engines, as well as to low combustion velocities attained. The above turned to be the main reasons for low impulse frequencies, high thermal and vibration loads, elevated noise level, and finally the unsatisfactory engine performance as a whole.
Keywords: pulse engine, periodic fuel combustion, resonator, detonation waves, autooscillation
Thermogasdynamic simulation of the gas turbine engine working process.
The article is focused on the use of gas turbine engine working process virtual models in connection with ASTRA CAE-system.
The theoretical framework is based on the methods of gas turbine engine working process theory, systems analysis, operations research, optimal control theory, mathematical simulation, calculus mathematics and computer-aided designing.
Method of gas turbine engine working process virtual models generation in connection with ASTRA CAE-system is developed. The described approach was approved on the designing of high efficiency multi-purpose gas generator, prospective bypass engine of 30 tons thrust, gas turbine locomotive power plant, during the computational modeling of Tu-154M and An-124 flight cycles and other research studies.
The results have shown good coincidence with experimental data and the results of specialized mathematical models and computer-aided systems, developed and used by the design offices.
The described approach and developed method of gas turbine engine working process virtual models generation may be used by the design offices of the aviation propulsion engineering industry during the designing, research and development of prospective gas turbine engines and power plants.
Use of the developed method provides more fast, more extensive and detailed investigations on the initial stages of gas turbine engine designing as well as design data refining using the results obtained at the following designing stages. Thus the reducing of design time and improvement of gas turbine engine characteristics is attained.
Keywords: computer-aided system, thermogasdynamic calculations, analysis, gas-turbine engine
This article examines modern or perspective turbofan engine for multipurpose maneuverable aircraft.
In this kind of engine, the ratio between fuel consumption at maximum rating and at ground idle is approximately 50. Therefore it is necessary to apply multi-collector combustion chamber.
The subject of this article is controlling of aircraft turbofan transient rating and fuel distributing to main combustion chamber collectors.
The purpose is to minimize the time of full acceleration; to improve the air-to-fuel performance; to improve the completeness of fuel combustion at steady-state rating.
There were analyzed the rules of fuel distributing to main combustion chamber collectors accomplished by standard (serial) fuel distributor. Defects of this scheme (design) were discovered. There were analyzed all the important influences on characteristics of transient rating and full acceleration of turbofan. There were analyzed the restrictions on choosing method of fuel distribution to the main combustion chamber collectors.
The preferable rules of fuel distribution to the main combustion chamber collectors were chosen. There was developed a structure of digital gas turbine power plant control system which is able to accomplish this kind of fuel distribution.
The results can be applied for aircraft turbofan engine controlling by full authority digital electronics (FADEC). The implication of the proposed control system structure is advisable for multi-collectors main combustion chamber and fuel batcher digital control system.
The developed structure allows to reduce the time of full acceleration up to the modern standards; to avoid working with unfilled main consumption collector; to improve the air-to-fuel performance and completeness of fuel combustion at steady-state rating.
Keywords: GTE, transition process, multilink control, fuel to combustion chamber
Control and navigation systems
The paper is devoted to the development of practical engineering methods of continuous real-time assessment (identification) of the unknown object parameters, which is based on the signals of measurement of input and output object coordinates.
The subject of the paper is connected with the proposed idea of independent (separate) evaluation of any/each of the unknown object parameters (e.g., dynamic coefficients of the airplane).
The paper aims at developing some practical methods and algorithms for separate estimation of the unknown parameters of static and dynamic aviation system objects.
The research method is based on preliminary formulation of a required system of equations with variable coefficients according to the signals of measurement of the input and output object coordinates. This equation system can be used for estimation of all unknown object parameters. Such system can be constructed, for example, on the basis of signals that contain current and past values of all measured coordinates. These values can be obtained by passing the signal through dynamic elements such as pure time delay links. Such signal processing provides for continuous calculation of the Cramer formulas determinants for the formulated equations system. This allows performing a reduction of the overall objective of estimation of all the unknown object parameters to a number of independent tasks of assessment of separate unknown parameters. After that these problems are solved via application of the methods of estimation of a single parameter in the presence of “measurement noise” such as the method of minimization of the current value of the squared error.
The estimation methods and algorithms, which were obtained during the research, can be used for the assessment of airplane dynamic coefficients as well as gradients of devices of object coordinate measurement or control channel. The paper presents some examples of obtaining the appropriate estimation algorithms and illustrates their effectiveness with the mathematical modeling results. This allows recommending the developed methods and algorithms of estimation of unknown object parameters for practical application, which will result in improvement of the quality of aircraft control systems.
The research proved the possibility of obtaining particular algorithms of automatic continuous evaluation of parameters of the static objects and dynamic objects, which can be considered as static objects, in the presence of “measurement noise”.
Accurate real-time measurement of aircraft control parameters is essential for enhancing its handling qualities. However, it is hard to assess these parameters precisely due to a number of complications. The paper offers a practically proven method for solving this problem.
Keywords: estimation, determinants of Cramer formulas, the residual error, the squared error, static objects and dynamic objects, dynamic airplane coefficients
The paper describes the possible ways of usage of standard coordinate system for piloting and orientation of aircraft and objects under observation.
The topic of the article is the theory and algorithms of elevation angles calculation for determination of aircraft position relative to ground target.
Operating of military aircraft connects with determination geodesic position for quick detection and connection targets to the map. The information about aircraft position, direction target line of sight allows detect the target position and auto-tracking by means of algorithmic computation.
There were used methods of mathematical and algorithmic description in the proposed article.
As a result of the work the system concept for determination of target position relative to aircraft, aircraft coordinates correction relative to object under observation position determination and auto-tracking, when the full inf
oware is available or in case of the trouble with the aircraft system, were developed.
Algorithmic methods suggested in the article allow to correct aircraft self-contained INS when GPS data are absent; define coordinates of objects under observation without range information if elevation data are available; and auto-track selected object with certain geodesic coordinates according to information about aircraft position.
The results of this work are useful for air force and helicopters.
Keywords: coordinate system, coordinate transformation, correction aircraft coordinate, target designation, tracking of targets
The development of algorithms for improving ofthe vibration resistance of navigation equipment performingmajortasksina guidance system under strong vibration impactscan be provided without any additions or modifications of the receiver hardware. It is based on the method of impactcompensation by meansthe softwareprocessing of the additionaldata from receiver common broadbandtracking loop. This approach is to compensate common channel interferencesfor satellites,e.g. vibration, by forming an additional general targeting for controlled oscillators for all satellite channels. This targeting allows one to remove an additional dynamic impact from PLL system.
The possibility of usingthe common broadband tracking loop for guidance control tasks in mobile GNSS applications was confirmed by experimental studies. Experiments have shown there are no observed reduction of satellite tracking compared tothe conventional receiverfor the impact of thevibration with the frequency rangefrom 8 Hz to 40 Hz and accelerationsmore than 3.5 G. That allows one to continue running the main tasks in case of such vibration impacts.Considered methods allows one to expand the functionality of navigation receivers which increases the total quality ofnavigation equipment applied in industrial automatic and semi-automatic control tasks.
Keywords: GNSS, GPS, GLONASS, quartz oscillator, phase-locked loop, ,
Radio engineering. Electronics. Telecommunication systems
The method of two-channel adaptive cancelation of narrow-band non-correlated disturbances is presented in this paper. The method used in the model disturbances canceller is based on adaptive modeling a mix of a desired signal and a disturbance in the basic channel and disturbance in the reference channel. To increase of the compensative accuracy in the reference channel, the additional adaptive filter is used, which not only equalizes disturbance level in channels, but it also corrects the disturbance correlation function in the basic channel as much as possible leading it to approach the correlation function in the reference channel. The proposed framework can be applied to cancel narrow-band disturbances in multichannel systems, telecommunication systems, and mobile communication systems. In the case of signal-disturbance power ratio lesser than minus 10 dB and the equality of disturbances power in channels the adaptive alignment allows to raise even more the degree of cancelation and to decrease error probability twice. Moreover, the method has proven to be useful in the case of mutually uncorrelated and unequal power disturbances in channels.
Keywords: model disturbances canceller, forming white noise, compensating filter
The progress in the development of electromagnetic radiation shielding and absorbing materials includes a synthesis of composite liquid-containing materials. The mechanical parameters of the materials are ensured by a porous matrix (which can be ordered or disordered, fibrous or powder) and a polymer binder. The shielding effectiveness of the composite materials is produced by the properties of the liquid, which fills the pore space of the matrix.
The stability of the electromagnetic parameters of the liquid-containing materials mainly depends on the temperature dependence of the water dielectric permittivity and doesn’t change significantly up to a temperature of +50°С. The issue of interest is the investigation of the material characteristics behavior at the points of phase transformation of water, which is the main component of such shielding materials.
The work is aimed at exploration of the influence of the physic-chemical processes, taking place in the volume and on the surface of the liquid-containing composite materials, when the temperature alters in a wide range, upon the stability of their shielding characteristics.
The liquid-containing powder and fibrous adsorbents in a silicone polymer were subjected to a step heating up to +150°С under a gravimetric control of their residual water content and shielding characteristics through measuring the EMR transmission and reflection coefficients in the frequency range of 8…12 GHz by a scalar network analysis technique.
Development of weather-proof electromagnetic shields and absorbers is as important as to ensure the high shielding effectiveness. The influence of the adsorbent matrix type and solution content upon the shielding effectiveness was determined. The samples based on fine powders are characterized by a high flexibility, good manufacturability and shielding effectiveness comparable to the similar thicker samples. The EMR reflection coefficient of powder-based samples 2 mm in thickness on a metal plate is -8.5…-12.0 dB for water-containing samples and -13.0…-17.8 dB for the samples, containing the hygroscopic solution.
The composite materials based on liquid-containing powders, distributed within an elastic polymer, are suggested for flexible electromagnetic shields and absorbers designs, capable of effective protection of stationary and mobile objects under high temperature, with a high stability of their shielding characteristics.
Keywords: electromagnetic radiation shield, composite materials, liquid-containing matrrials, temherture dependency of shielding effectiveness
The purpose of present work is the development of the electromagnetic radiation shielding constructions based on crude iron production powdered waste (sludge treatment cupola gases), representing, as well as ferrites, metal oxides compounds. For purposes of this research sludge treatment cupola gases, characterized by the certain fractions size, was poured in a container with a rectangular cross section, made of radio transparent material and containing an insert made of molded pulp, and having a rectangular recess in the form of truncated pyramids slurry. Shielding characteristics measurements (reflection and transmission coefficients, power of the electromagnetic radiation passing through the shielding construction) were conducted in the frequency range from 0,8 up to 18 GHz using panoramic meter transmission and reflection coefficients, the transmitting and receiving antennas, electromagnetic radiation power meter. It was found that the magnetic properties and grain size of sludge treatment cupola gases have a greater impact to the transmission coefficients than reflection coefficients of electromagnetic radiation shielding constructions produced on the basis of sludge treatment cupola gases.
The developed electromagnetic radiation shielding constructions can be mounted on the walls of anechoic chambers, in which high-precision and sensitive to electromagnetic interference equipment (satellite systems, ground penetrating radar, marine beacons, etc.) is tested. Also it’s possible to implement multi-layered design electromagnetic radiation shields of gradient type on the basis of powdered sludge treatment cupola gases using technology described in this paper. Furthermore, the sludge treatment cupola gases can be used as filler in the manufacture of single and multilayer electromagnetic radiation shields of composite type, characterized according to the type of binding solution (portland cement, silicone, etc.) by various physical properties, in the manufacture of coating or filling solution for electromagnetic radiation shielding constructions with geometrically inhomogeneous surface.
Keywords: reflection coefficient, transmission coefficient, relative permeability, crude iron production powdered waste, shielding, electromagnetic radiation
The short review of properties and scopes is provided in article developed and investigated in «СIAM» Federal State Unitary Enterprise together with JSC «Diaprom» and JSC «Kuznetsov» of the nanostructured superfirm composite materials and coverings on their basis. The carried-out research works allow to draw a conclusion on big prospects of application of the nanostructured composite materials on the basis of carbides, carbonitrides and diborides transitional and refractory metals for aerospace objects.
Subject of this work is consideration of scopes of the created superfirm composite materials.
Creation of superfirm composite materials and powders on their basis for receiving coverings and monolithic composite materials for the purpose of increase of a technological level of aerospace objects was the purpose of this work. The created coverings and monolithic composite materials allow to create for aerospace objects both the aerospace industry units and devices of new generation. The method of work had research and experimental character directed on the solution of specific practical objectives.
As a result of the carried-out works composite materials of new generation with operated electro - physical properties were created. These materials allowed to create various units of new generation for aviation engines, aerospace objects and the aviation industry, significantly having increased their reliability and a resource.
The created composite materials and designs from them already found application in various units of aviation engines (pumps, reducers, hydraulic cylinders, bearings), in designs of aerospace objects (sheetings of a glider of the aircraft, bearings of mechanization of a wing, pneumatic cylinders), in the aviation industry (industrial equipment, wearproof details of high-precision machines).
particularly the (re)introduction of accrual accounting, and provides insights into the nature of accounting change both in public sector organisations and generally.
As a result of the done work the new family of composite materials which allowed to create designs of units and mechanisms in the aircraft equipment and the aviation industry of the new generation, working at the new original principles is created.
Keywords: nanostructured materials, refractory carbides, carbonitrides, diborides, friction coefficient, disperse strengthened, antifrictional materials, antifrictional coverings, ,
Economics and management
The problem of modernization of the domestic industry costs today especially sharply. In the conditions of market economy and the competition those producers who effectively use the resources successfully function.
Efficiency of economic activity of the enterprise is defined by the organization of formation of its financial resources.
Feature of the aircraft repair enterprises is formation of sources of financial means at the expense of own capital in the form of the authorized, reserve and additional capitals, insignificant dependence on external sources of financing that doesn't allow to attract and use enough of resources.
For ensuring continuous economic activity with necessary financial resources, the system of financing of the aircraft repair enterprises has to be adapted for requirements of the modern market. For this purpose it is necessary to develop the long-term financial plan coinciding on the terms from state program of development of aviation branch as a whole.
The increase in volume of repair, equipment service at reduction of term of performed works with an entry into the international market has to become strategy of development of the aircraft repair enterprises.
For realization of this strategy of the organization have to optimize system of financing of a production activity, increase a share of the borrowed funds allocated for modernization and expansion of production.
Main purpose of the industrial enterprises is the increase in their market cost that is interfaced to a large number of risks, management with which allows the organization to function and achieve successfully goals with the minimum losses.
Main purpose of the industrial enterprises is the increase in their market cost that is interfaced to a large number of risks, management with which allows the organization to function and achieve successfully purposes with the minimum losses.
For modernization and production expansion the aircraft repair enterprises need to attract external investors. Therefore the risk of decrease in investment appeal has decisive impact on possibilities of further development of the organization. For volumes of investment depends, whether the branch will be able to adapt for requirements of the modern world, to develop in parallel with becoming complicated technologies and needs of customers.
To make the weighed decision on expediency of implementation of this or that investment project, and at its acceptance to try to minimize the possible losses caused by risks inherent in it, the careful comprehensive analysis of the project assumed to implementation, a correct assessment of risks inherent in it is necessary.
For an assessment of investment risks most optimum to use a method of imitating modeling of Monte-Carlo. This method allows to estimate complex influence of factors on results of investment.
Keywords: financial resources, aviation industry, risk, investments, simulation, project, efficiency
The development of the method of production management, which helps to raise the quality of production planning, reduce production costs, shorten production cycles and reduce the parts in work in progress. The development of the system design and implementation of the project-process approach, organizational management mechanism on the example of the approach to aero engine company.
Project and process-oriented approach is based on a combination of project and process management, takes into account the characteristics of each method. The possibility of applying the elements of project and process approaches to the management of the company aircraft engine production. The expediency of the use of project-process approach. Use the synergy method to evaluate the effects from the implementation of the approach. Use the statistical method to the information of the results of an approach to aero engine company.
A scheme of design and implementation of the project-process approach, describes each of the stages of the approach. The organizational management mechanism, improve the performance of listed companies. The approach can be applied to aircraft engine building, as well as other machine-building enterprises, including multinational companies and holdings.
The use of project-process approach has significant results in an enterprise aero engine: more efficient use of resources of the enterprise, improving the quality of planning at all stages of the value chain of the final product cost reduction in order to achieve the target cost, which is a measure of actual output in Russia in the world market of this industry.
Keywords: project-process approach, implementation stages, classification of risks