bluuebunny/crossref_metadata_2025 huggingface dataset:
ЗАКОН РАСПРЕДЕЛЕНИЯ РАЗРУШАЮЩИХ НАГРУЗОК ЭЛЕМЕНТОВ КАРКАСА КУПОЛА ПАРАШЮТА
Authors: Фомичев Петр Александрович , Сила Игорь Михайлович
Published: August 2019

It is known that during operation or long-term storage, there is a significant deterioration (degradation) of the strength characteristics of the strength elements of the parachute canopy’s carcase, including shroud lines, canopy’s fabric, reinforcement tapes, free ends of the suspension system, leg straps, etc.Parachutes are designed considering the specific safety factors of power elements for the extreme loads resistance at the moment of parachute opening. Further operation after the specified period with unchanged safety factors is possible only in flight conditions limitation, in particular, landing speeds. Strength characteristics are characterized by significant scattering. The design of parachutes is carried out considering the guaranteed values of destructive loads of elements with a given level of reliability. In this case, the law of destructive loads distribution must be known.It was tested the normal distribution applicability of the strength characteristics applying the compound compliance criterion. The basis is the data of strength tests until the destruction of shroud lines samples and fabric of the canopy warpwise and wefting. The samples were cut from D-5 series 2 parachute of the year 1983, Z-5 reserve parachute of 1984, the rescue parachute C-5 K series 2 of the 1989. It was tested totally 301 samples of various materials from these parachutes. At the first stage of processing the test data, by experimental determination of the breaking load, the gross emissions were rejected, then a composite criterion for compliance with the normal law was applied.According to the results of comparison with experimental data, the validity of the normal distribution of destructive loads for the shroud lines and canopy’s fabrics both warpwise and wefting is unambiguously shown. The obtained result makes it possible to evaluate the strength characteristics of the carcase elements after operation or long-term storage with the required level of reliability and, in the future, to find the strength degradation factors of the power elements. These factors will limit the maximum allowed landing speed with a specific parachute.
АВТОМАТИЗОВАНЕ ВИРОБНИЦТВО ВІДВОДІВ СКЛОПЛАСТИКОВИХ ТРУБОПРОВОДІВ
Authors: Криживець Євген Олександрович , Ківіренко Олег Борисович , Комбаров Володимир Вікторович
Published: August 2019

A promising direction in the production of high-pressure pipelines is the use of composite materials with special properties. Characteristics of composite products are set by reinforcement schemes and the use of various binders. The stability of the strength characteristics significantly depends on the stability of the process of laying reinforcing fibers. The development of automated technological systems of production, ensuring the stability of the process, is an urgent task. A method of fiberglass pipe bends manufacturing by the method of pre-impregnated tape winding on a folding mandrel. To implement this method the problem of developing technological equipment, equipment and methods of adjustment are solved. The proposed solution provides the formation of a branch from the inner surface. The kinematic scheme of the equipment realizes the rotation of the tape stacker around the axis of the cross-section of the mandrel and the longitudinal-angular displacement of the mandrel relative to the stacker, which provides the possibility of cylindrical and spiral stacking of the tape. The installation of tap winding, which is a three-axis CNC machine that implements the proposed scheme, is described. The rotation of the coils with tape around the mandrel is provided with a hollow rotary axis – stacker. Moving the mandrel relative to the stacker is provided by its installation on a movable platform. Following the proposed method of manufacturing bends, the outer surface of the collapsible mandrel ensures the formation of the inner surface of the branch, including the connecting-butt surfaces. Rules for the choice of the surface of the connector mandrel, ensuring its extraction from the manufactured branch is formulated. A method for programming winding operations has been developed. A method for determining the parameters of the control system of the CNC system is given, which specifies the structure of laying the tape and the wall thickness of the outlet. A procedure is described for setting up a tap manufacturing operation consisting in changing the relative position of the installation elements and the mandrel fixing devices. The use of traditional for CNC systems approaches to adjust the coordinate systems ensures the accuracy of the initial position is not worse than 0.1 mm.
ЭКОНОМИЧЕСКАЯ НЕОБХОДИМОСТЬ СОЗДАНИЯ МОДИФИКАЦИЙ ОТЕЧЕСТВЕННЫХ ВОЕННО-ТРАНСПОРТНЫХ САМОЛЕТОВ
Authors: Лось Александр Васильевич
Published: August 2019

The state enterprise "Antonov" is one of the leaders in the world in the development and commissioning of modifications of transport-grade aircraft, including military transport aircraft. The cost of developing and mastering serial production of new MTA and aircraft engines is, as a rule, several billion dollars, so for the project to pay off, it is necessary to implement it through the creation and commissioning of modifications to the already existing basic options. This inevitably raises the problem of correct comparison of the operated MTA and its modifications.Currently, there is no acceptable methodology for determining the level of competitiveness of complex industrial products, including aviation. Product competitiveness is a complex concept that requires a multi-faceted assessment. An important component of such an assessment is the cost indicators of the newly created modification, such as: the cost of modifying a new aircraft, the cost of aircraft hours, hourly fuel costs, etc.The paper shows that the cost parameters of the modifications largely depend on the type of aircraft (light, medium or heavy) and on the year the modification was presented in the air transportation market.The analysis of changes in prices of domestic light, operational-tactical and heavy MTA in the comparative setting with competitors-analogues is given. It follows from the analysis that these domestic aircraft were competitive at their price until 2012, and now there is an economic problem of increasing their competitiveness by carrying out profound modification in the wing and in their power plant in these previously created aircraft.The solution of this problem is carried out by geometrical rearrangement of the wing (to improve its aerodynamic quality) and the replacement of cruise engines with lower specific fuel consumption. Modifications were created in this way: on the basis of An-32B – An-132D with specific fuel consumption of 223 g/t∙km, on the basis of An-148 – An-178 with specific fuel consumption of 222 g/t∙km and on the basis of An-70 – An-188 with a specific fuel consumption of 154 g/t∙km at maximum capacity.Considering that the cost of hourly fuel consumption takes about 70 % of the cost of an air-hour, the results obtained significantly increase the competitiveness of the above-mentioned MTA.
SELECTION AND OPTIMIZATION OF FUSELAGE COMPONENTS FOR MODERN AIRPLANES
Authors: Makarov Ihor Andriyovych , Ignatovich Sergey Romualdovich
Published: August 2019

Nowadays the level of development of airplane materials shows the tendency of usage of advanced composite structures. However, these materials have plenty of advantages and disadvantages, the most crucial is the ability to absorb water from the environment and because of this layers of composite structures disbonded and consequently became useless. This issue demonstrates the limitation of usage of advanced composite structures. Despite this fact application of conventional materials (such as Aluminum or Titanium alloys) are limited by the weight of structure and manufacturability. In given article question of optimization for choosing of the airplane, the material is considered. The necessity to maintain equilibrium between minimal weight and appropriate strength pushes designers to develop new advanced materials, mechanical properties of which satisfy strict criteria of strength, despite lightweight of the material.  The goal of this research elaborating work is to estimate the necessity of usage of advanced composite structures vs well known conventional materials.  It was researched sizing and optimization of choosing of structural materials for the primary structure. On top of this, properties and peculiarities of conventional materials (such as Aluminum and Titanium alloys) and advanced composite structure. It was demonstrated that the usage of conventional materials for primary structure has a significant advantage in comparison with advanced composite structures. Additionally, manufacturability and maintainability of materials were discussed in the given article. As a result, the application of conventional materials for primary airplane structure is the most suitable way for the design of modern airplanes. Today, the structural designer no longer chooses a material solely based on its strength qualities, but on its proven ability to withstand minor damage in service without endangering the safety of the aircraft. The residual strength after damage, described as the toughness, is now uppermost in the engineer’s mind when he chooses alloys for airframes. Damage caused by fatigue is the main factor because it is difficult to detect and can disastrously weaken the strength of critical components. So whereas about a decade ago aluminum alloys looked as if they had reached a technical plateau, engineers have now been able to clarify their needs as a result of the work done on fracture mechanics, and metallurgists have changed their composition and treatment techniques to meet the new toughness requirements. The best option to consider the usage of both advanced composite structure (for secondary structures) and conventional material (for primary structures).
МАЛОИНЕРЦИОННЫЙ ТЕПЛООБМЕННИК АММИАК-АНТИФРИЗ ДЛЯ ИССЛЕДОВАНИЯ ПЕРЕХОДНЫХ ПРОЦЕССОВ В ЭЛЕМЕНТАХ ДВУХФАЗНОЙ СИСТЕМЫ ТЕРМОРЕГУЛИРОВАНИЯ СПУТНИКА
Authors: Годунов Артем Михайлович , Роговой Евгений Эдуардович , Орлов Роман Сергеевич , Турна Рустем Юсуфович
Published: August 2019

Technical progress entails the use of more powerful equipment on satellites. In connection with the growth of heat generation onboard the spacecraft, the task is to develop thermal control systems based on two-phase mechanically pumped fluid loop (2PMPFL). The advantage of such systems is the ability to transport a greater amount of heat, reduced to a unit of flow, than when using circuits with a single-phase coolant. The study of two-phase thermal control systems in terrestrial conditions is difficult because gravity affects the hydraulics and heat transfer of two-phase flows. Particularly difficult is the study of transients. This article presents the results of tests of a recuperative heat exchanger, which allows to study transient processes in 2PMPFL with high accuracy.It was designed and manufactured the heat exchanger of simple “tube in tube” type design. The thermal characteristics of the heat exchanger were determined on the experimental stand, which is a prototype of a closed-type 2PMPFL with ammonia coolant. Single-phase “liquid” modes, two-phase modes with low mass vapor content (up to 0.04), and single-phase transient modes were investigated. It has been experimentally determined that a heat exchanger under given conditions is capable of removing up to 1323 W of heat in a single-phase mode and up to 1641 W of heat - when operating in a two-phase mode. The data obtained in the course of the experiments allowed us to select the most appropriate known correlation for calculating the stationary characteristics of the heat exchanger with an error not exceeding 5%, which is a high indicator of accuracy for engineering calculations.The heat exchanger has low thermal inertia. The conclusion is relevant for the range of parameters: the ammonia temperature at the inlet is 24...60 ⁰C; antifreeze inlet temperature 5… 16 ⁰C; ammonia mass flow rate 8...17 g / s; mass flow rate of antifreeze 1...4 kg/min.Due to the low thermal inertia of the heat exchanger, it can be used to study transients with the rate of change of the coolant temperature at the inlet up to 1.85 K / min. You can use the stationary method of thermal calculation, i.e. calculate the transient process in the quasi-stationary approximation.
ЕКСПЕРИМЕНТАЛЬНІ ДОСЛІДЖЕННЯ РОБОЧИХ ПРОЦЕСІВ В ТЕРМОАКУСТИЧНОМУ ТУРБОГЕНЕРАТОРІ
Authors: Коробко Владимир Владиславович
Published: August 2019

Thermoacoustic thermal machines (TATM) is a relatively new and non-common type of thermal machines that differs significantly from conventional mechanical systems due to the lack of moving elements, environmental safety, and the ability to operate from external sources of energy. Thermoacoustic engines (TAE) - direct-acting thermal machines that are capable of converting thermal energy into mechanical in the form of powerful acoustic waves. The growing interest to TATM is related to the possibility of using them in energy saving systems since the introduction of energy saving technologies is an effective method for increasing the efficiency of power plants and reducing their harmful effects on the environment. The wide introduction of TATM is hampered by their low specific power, the complexity of the transformation of acoustic oscillations into mechanical work and lack of experience.The article presents the results of experimental research on the operational characteristics of the thermoacoustic turbogenerator (TATG). The TATG consists of a thermoacoustic engine, which operates in the Brighton thermodynamic cycle and an electric generator. As an actuator of an electric generator, a pulsed bi-directional turbine was used. It is capable of converting the oscillatory motion of the working medium into mechanical energy. In the course of experiments, data were obtained on external characteristics of both TAE and TATG at different load conditions. The interaction of a pulsed bi-directional turbine with a pulsating working medium leads to the appearance of complex radial currents in the resonator that affects the efficiency of the energy conversion processes.In the work, using CFD simulation, the peculiarities of formation and development of radial currents were studied. Boundary and initial conditions were imposed based on experimental data. The results of CFD experiments allowed us to study the influence of various factors on the intensity of radial currents. It is shown that radial currents exist in the form of quasistationary pulsating structures whose length depends on the amplitude of the oscillatory motion of the pulsating medium and the frequency of acoustic oscillations. The presence of these currents leads to the "desired" flow of input into the rectifying apparatus of the impulse turbine. According to the results of the research, technical solutions are proposed that prevent the formation of such currents.
АНАЛІЗ ЕФЕКТИВНОСТІ ОХОЛОДЖЕННЯ ПОВІТРЯ КОГЕНЕРАЦІЙНОГО ГАЗОПОРШНЕВОГО МОДУЛЯ УСТАНОВКИ АВТОНОМНОГО ЕНЕРГОЗАБЕЗПЕЧЕННЯ
Authors: Радченко Андрій Миколайович , Зубарєв Анатолій Анатолійович , Фордуй Сергій Георгійович , Бойчук Володимир Володимирович , Цуцман Віталій Васильович
Published: August 2019

The analysis of the efficiency of cooling air of cogeneration gas-piston module of installations for combined production of electric energy, heat, and cold is performed. The installation for energy supply includes two JMS 420 GS-N.LC GE Jenbacher cogeneration gas-piston engines manufactured as cogeneration modules with heat exchangers for removing the heat of exhaust gases, scavenge gas-air mixture, cooling water of engine and lubricating oil. The heat of hot water is transformed by the absorption lithium-bromide chiller AR-D500L2 Century into the cold, which is spent on technological needs and for the operation of the central air conditioner for cooling the incoming air of the engine room, wherefrom it is sucked by the turbocharger of the engine. The temperature of the scavenge gas-air mixture at the entrance to the working cylinders of the engine is maintained by the system of recirculating cooling with the removal of its heat into surroundings by the radiator. Because of significant heat influx from working engines and other equipment, as well as through the enclosures of the engine room from the outside to the air-cooled in the central air conditioner in the engine room, from where it is sucked by a turbocharger, the air temperature at the inlet of the turbocharger is quite high: 25...30 °C. At elevated temperatures of the ambient air at the inlet of the radiator for cooling scavenge gas-air mixture and the air at the turbocharger inlet the fuel economy of engine is falling, which indicates the need for efficient cooling of air. The efficiency of cooling the air of the gas-piston module was estimated by a reduction in the consumption of gaseous fuel and the increase in electric power of the engine. For this purpose, the data of monitoring on the fuel efficiency of the gas-piston engine with the combined influence of the ambient air temperature at the inlet of the radiator and the air at the turbocharger inlet were processed to obtain data on their separate effects and to determine the ways to further improve the air cooling system of the gas-piston module.
ЗАСТОСУВАННЯ ГАЗОДИНАМІЧНОГО ОХОЛОДЖЕННЯ В СИСТЕМАХ РЕЦИРКУЛЯЦІЇ ВІДХІДНИХ ГАЗІВ СУДНОВИХ ДИЗЕЛІВ
Authors: Коновалов Дмитро Вікторович
Published: August 2019

There are many ways and methods to reduce exhaust gases emissions on modern ships. One of the most effective ways to reduce NOx and SOx emissions is to use of exhaust gas recirculation (EGR technology). The EGR system disadvantage is an increase in back pressure through additional pressure losses in the scrubber and heat ex-changer, which entails an engine fuel efficiency deterioration. Creating a reliable and efficient heat exchanger for cooling recirculation gases is a complex task due to deposits and pollution emitted by these gases. In the pre-sent work, the jet apparatus effectiveness named aerothermopressor is analyzed in the scheme with exhaust gases recirculation of the ship low-speed two-stroke engine. Aerothermopressor is a two-phase jet for contact disperse cooling, in which by increasing the heat from the gas stream the gas pressure and cooling are increased. The calculation of the characteristics of the engine was carried out, both in nominal, and in operating modes and in all possible range of partial loads. The installation of the aerothermopressor before the scrubber is pro-posed, which allows reducing engine thermal load. Increasing the pressure in the aerothermopressor by 0.2-0.4 ∙ 105 Pa (6-12 %) allows reducing the back pressure in the gas exhaust system and thus reducing the load on the exhaust gas recirculation fan and when the engine load is higher than 75% in the cold zone, the fan is not need-ed, which additionally allows to reduce the specific fuel consumption. The parameters of the exhaust gases that are going to be recirculated and the processes of their gas-dynamic cooling in the aerothermopressor are based on the developed technique and program using the thermodynamic and gas dynamics equations. The proposed scheme-design solution allows at a high environmental friendliness of the existing exhaust gas recirculation sys-tem to provide a certain reduction in specific fuel consumption. It was determined that the engine specific fuel consumption has been decreasing when the aerothermopressor is used to Dge = 2.5-3.0 g/(kW·h) (1.5-1.7%).
ПАРАМЕТРИЧЕСКАЯ ОПТИМИЗАЦИЯ ПО КРИТЕРИЮ ОБЪЕМА ДВУХСТУПЕНЧАТОГО ПЛАНЕТАРНОГО МЕХАНИЗМА ТИПА AI–II
Authors: Матусевич Владимир Анатольевич , Шарабан Юрий Владимирович , Шехов Александр Владимирович
Published: August 2019

The task of parametric optimization on the criterion of total volume is considered for the two-stage planetary mechanism of type AI–II. The objective function of optimization is built as a sum of two dimensionless parametric functions of volume (analogs of volume) of the separate stages of planetary mechanism of type AI–II. Construction of analogs of volume of simple planetary mechanisms of type AI and II, corresponding the first and second to the stages of planetary mechanism of type AI–II, it is based on their presentation as conditional disks. Thus the volume of the conditional disk is equivalent to the volume of a simple planetary mechanism. The mathematical model of analogs of the volume is built taking into account the terms of the durability of the toothed hooking of the sun gear and planetary gears of simple planetary mechanism, and also taking into account an area possible his transmission relation. Considering terms of contact and bending durability of the toothed hooking, get the analogs of volume at a calculation on contact and bending to durability. Depending on the condition of durability (contact or bending) and type of simple planetary mechanism the analog of his volume appears as a parametric function of corresponding parameters of his kinematics diagram. As parameters transmission relation attitude of simple planetary mechanism, parameters of bringing a mechanism over, toward a conditional disk, and also the relation of reference diameters of planetary gears of the mechanism is chosen. An analysis over of influence of each is brought of parameters of the function of analog of volume on the pattern of behavior to it. On the basis of this analysis of function of analogs of volume of the stages of planetary mechanism of type AI–II appear as parametric functions of the guided parameters. For the simple planetary mechanism of type AI one guided parameter is chosen, namely transmission relation of mechanism. For the guided parameters of function of analog of volume for the simple planetary mechanism of type II a transmission relation and relation of reference diameters of planetary gears of mechanism are chosen, i.e. two guided parameters. Offered approach for the decision of optimization task, based on research of differential properties of objective functions of volume (analogs of volume) of the separate stages of planetary mechanism of type AI–II. It is given the example of the optimal designing of construction of minimum volume of planetary mechanism of type AI–II.
ЭКСПЕРИМЕНТАЛЬНОЕ ПОДТВЕРЖДЕНИЕ РЕТРОСПЕКТИВНОГО МЕТОДА УСТАНОВЛЕНИЯ РЕСУРСОВ АВИАЦИОННЫХ ГТД
Authors: Шереметьев Александр Викторович
Published: August 2019

There was done experimental confirmation of competent using the retrospective method of GTE service life establish. The data of the twenty-two years of the exploitation of the GTE with the high stage of the two contours and comparison of the obtained results with the exploitation of the foreign engines in the same class shows the good agreement. It testifies reliable retrospective method establishing the service life which was developed in the SE “Ivchenko-Progress” and expediency of using this method in the future. At present there is the goal before the engineers of the aviation companies: “…the goal is to make in a year the same work for the creation of aero-engines which was done earlier in five years and expense 1 billion dollars for the work where we expensed in the past 6 or 7 billion dollars”. To achieve such goals we must change the methodology of the creation of the GTE. For the reducing the time and expenses in creation, working out and certification it is necessary to create new methods for providing strength reliability to achieve a high level of the reliable of the results with the combination of acceptable expenses of time and money. The improvement of the methods of providing strength reliability on the base of strength analysis and experimental research works which were done earlier, experience of working out and service of the constructive – similarity parts of the engine – prototypes make it possible to minimize the time and expenditures at the developing, working out and certification of the new aviation GTE. The using of the constructive – similarity conception with the combination of the experience of the creation, working out and certification aviation GTE at the availability of the contemporary powerful calculation technique and software for the determine thermo-mechanical stress-straining condition of the parts makes it possible to successfully solving the task of providing strength reliability parts in the condition of the complex poly factory loading. In this case, it may achieve an essential saving of the expenditures and time, including also the period of the establishing of the service life. The success service of the engines with the high stage of two contours at the limits of the establishing cycle life of the main parts with the using the retrospective method confirms its authenticity and advantages with others methods of service life establish.
ДЕМПФИРОВАНИЕ КОЛЕБАНИЙ ОХЛАЖДАЕМЫХ ПОПАРНО БАНДАЖИРОВАННЫХ РАБОЧИХ ЛОПАТОК ТУРБИН
Authors: Шакало Руслан Юрьевич , Придорожный Роман Петрович , Якушев Юрий Владимирович , Меркулов Вячеслав Михайлович , Зиньковский Анатолий Павлович
Published: August 2019

The cooled turbine blades are the parts that determine the reliability and service life of a gas turbine engine. As is known, most cases of engine failure are related to the destruction of turbine blades. Turbine blades during operation experience high thermal stresses, the stresses from centrifugal and gas forces, as well as dynamic stresses. This paper presents methods for ensuring an acceptable level of dynamic stresses in turbine blades. One of the most effective methods is considered in more detail - pairwise shrouded cooled turbine blades. The effectiveness of the damping of such working blades depends on the guaranteed contact of the contact surfaces of the flanges of the shanks and banding shelves and the optimality of the shroud connection. As the object of the study, we chose pairwise shrouded turbine blades from the engine, on which there were several cases of destruction of the turbine blades. To assess the optimality of the bandage connection of the working blades under study, a scheme has been developed for calculating the force acting on the contact surfaces of the banding shelves. According to the developed scheme, calculations were made of the forces acting on the contact surfaces of the retaining shelves, both of the investigated working blades, and similarly pairwise shrouded cooled turbine blades, developed by SE «Ivchenko-Progress». After calculating the force acting on the contact surface of the retaining shelf, the ratio of the received force to the parameters of the feather profile, such as chord and CMAX, is calculated. According to the data obtained, a graph of the dependence of the voltage in the blade on the relative force acting on the contact surface of the retaining shelf was plotted. The analysis of the obtained graph made it possible to conclude that there is an optimal force at which dynamic stresses will be acceptable. However, since a small sample of pairwise shrouded cooled turbine blades is presented, it is necessary to continue the work on determining the criteria for optimality of the shroud linkage and on clarifying the resulting relationship.
ПОЛУЧЕНИЕ ВЫЖИГАЕМЫХ МОДЕЛЕЙ МЕТОДОМ 3D-ПРИНТИНГА ДЛЯ ОТЛИВОК ГАЗОТУРБИННЫХ ДВИГАТЕЛЕЙ
Authors: Лысенко Наталия Алексеевна , Педаш Алексей Александрович , Клочихин Владимир Валерьевич , Наумик Валерий Владиленович
Published: August 2019

A study of the fuse deposited pattern and castings of gas turbine hot section, which was obtained with additive manufacturing, has been carried out in the present article. A pattern of the castings had been produced by selective laser sintering (SLS) process from the polystyrene powders according to developed in special program complex 3D-model. With involving of the obtained FDM-pattern via burned pattern casting process have been produced a parts of gas turbine hot section from nickel-base superalloy VKh4L-VI. The castings were investigated as in the as-cast state, thus and after inherent superalloy VKh4L-VI heat treatment with prior hot isostatic pressing (HIP). An analysis of the obtained FDM-pattern for the presence of surface defects and geometry compliance are provided, together with the macro- and microstructure study of obtained castings and evaluation of mechanical properties and stress rupture strength results. It was established that investigated patterns as precisely as possible reproduce dimensions accuracy of the parts, and castings had satisfactory surface cleanliness, roughness, dense and middle crystalline macrostructure. Micro-structure of castings material is typical for nickel-base superalloy VKh4L-VI in the as-cast state with carbides, carbonitrides and eutectic phase’s presence.HIP with subsequent heat treatment provides almost full micro porosity releases in the inner volumes of the metal and getting more uniform solid-state, almost full eutectic dissolving, and carbides dispersivity. Mechanical properties and stress rupture strength (rupture life) of the specimens produced by considered production processes meet the specification requirements. Application of HIP with subsequent heat treatment (homogenization and ageing) for specimen’s production provides slightly bigger indexes of mechanical properties at room temperature.Selective laser sintering application for FDM-patterns production made it possible to obtain qualitative castings with satisfactory microstructure, the acceptable level of the properties and realize traditional advantages inherent for both considered processes.
РОЗРАХУНОК ТЕМПЕРАТУРНО-ШВИДКІСНИХ ПАРАМЕТРІВ ЧАСТИНОК ПРИ ХОЛОДНОМУ ГАЗОДИНАМІЧНОМУ НАПИЛЮВАННІ
Authors: Шорінов Олександр Володимирович , Волков Андрій Олегович , Маркович Сергій Євгенійович , Долматов Анатолій Іванович
Published: August 2019

The method of computational fluid dynamics (CFD) for the supersonic nozzle SK-20 of the low-pressure cold gas-dynamic spraying equipment DYMET-405 was applied for calculation of particles impact temperature and velocity. The application of the CFD method is the one-dimensional isentropic gas-dynamic model considers the flow only along the nozzle axis, without taking into account the heat exchange with the nozzle and the friction losses on the internal walls, which leads to obtaining overestimated results of calculations. Previously it was found out that the difference in the values obtained by numerical simulation and the results of calculations of a one-dimensional isentropic model was less than 10%. Numerical simulation of the two-phase flow of the cold spray process has been performed using the Ansys Fluent Academic software package. The influence of the initial cold spray process parameters such as temperature and pressure at the nozzle inlet on the change in temperature and velocity of aluminum particles with a diameter of 25 μm at the moment of impact with the substrate has been studied. Also, the influence of the particle size on the above-mentioned parameters has been obtained. The numerical simulation results of the particle impact temperature with the substrate have been used to calculate the critical velocity of aluminum powder – the velocity needed for coating formation. It is known that the formation of cold spray coatings depends on the velocity of the powder particles. For each material, there is a critical velocity at which the process of forming the coating begins. At particle velocities above the critical one, their adhesion to the substrate and the formation of the coating, due to the plastic deformation of the particles, occurs, while at lower velocities the surface erosion or deposition with low efficiency under certain conditions is observed. As a result of simulation and calculations of the critical velocity, the window of spraying was developed, that is the region of values of velocities and temperatures of the particles of aluminum powder, depending on the temperature and pressure of the air at the nozzle inlet, at which the formation of coatings is possible.
КОНСТРУКТОРСЬКО-ТЕХНОЛОГІЧНА ПІДГОТОВКА ВИРОБНИЦТВА ДЕФЛЕКТОРА З ВИКОРИСТАННЯМ ІМПУЛЬСНИХ ТЕХНОЛОГІЙ
Authors: Онопченко Антон Виталиевич
Published: August 2019

The development of explosion punching processes is a rather complicated task for preparing the production of aircraft engines. The relatively large complexity and duration of production preparation, as well as the relatively high cost of the dies, require careful development of technological processes and an informed choice of a technically rational and cost-effective version of the technological process that corresponds to a certain scale of production. Even small further changes in technological processes usually lead to the processing of dies or the design and manufacture of new ones that require considerable time and are quite expensive. The design features of the thin-sheet part, which is an integral part of the D-136 turboshaft engine, which is used on Mi-26 heavy transport helicopters, are analyzed. The deflector has a domed shape, stiffening ribs are provided for stiffening the shape of the part - axisymmetric. After stamping-hoods, it is necessary to apply machining (drilling holes on the flange for mounting the deflector). The accuracy of the part is determined by the accuracy of processing the working surface of the matrix. Deviation of the part profile from the working profile of the matrix depends on the dimensions of the part. The technological process of stamping by the explosion of a deflector is developed, which consists of several stages: analysis of the structural and technological features of the part; determination of the shape and size of the workpiece, as well as the consumption of material; the choice of a rational technological process that ensures the manufacture of the necessary parts; determination of the type of equipment needed; selection of type and technological scheme of the stamp, and determination of the complexity of manufacturing stamped parts. A mathematical for describe the design of the deflector, which consists of several levels of complexity model is developed. Each level of the design description is responsible for its own stage of the technological process. Based on the developed model, an algorithm and a program for calculating the parameters of the technological process are created.
ВИЗНАЧЕННЯ ДИНАМІЧНИХ ХАРАКТЕРИСТИК ВИКОНАВЧИХ ОРГАНІВ ТЕХНОЛОГІЧНОГО ОБЛАДНАННЯ
Authors: Комбаров Володимир Вікторович , Аксьонов Євген Олександрович , Цегельник Євген Володимирович , Криживець Євген Олександрович , Задорожний Сергій Миколайович
Published: August 2019

The production of complicated profile parts for aerospace technology is carried out by processing along spatial paths. The nature of the movement of each axis of the equipment is dynamic and unsteady-state. Accuracy must be ensured not only in a steady-state but also in dynamic mode. The determination of dynamic characteristics of the executive bodies is an important and urgent task to optimize the control process. An experimental research method using capabilities of the CNC system, which was equipped with additional hardware and software, is proposed. This allows to register a large number of parameters that describe the state of the equipment, the solving of the task of trajectory interpolating, the formation of control actions, the actual movement of the executive bodies. The methods of conducting experimental studies with the setting of a stepwise change in speed and with a change in speed according to the harmonic law for an open-loop and closed-loop system using various components of the feedforward in the regulator are considered. The use of circular interpolation for the formation of a harmonic law of speed change is proposed. The results of the study of the dynamic of the transition process of an open system are shown. The frequency characteristics of the drive under study are obtained. Its bandwidth is determined. The study of the moving process when the axis velocity changes in harmonic law was performed within the passband. The possibility of determining the maximum permissible values of inertial loads by the nature of the change in actual acceleration is shown. The influence of the regulator feedforward composition on the accuracy of positioning of the servo drive and the accuracy of the contour processing at various frequencies of the control action is studied. For each feedforward method, the frequency ranges of the control action are determined, on which the specified processing accuracy is ensured. It was found that the technological frequency limitation by the accuracy of the reproduction of the path turned out to be significantly more stringent compared to the classical approach for determining the bandwidth.
МЕТОД ПРОЕКТИРОВАНИЯ ЭЛЕКТРОГИДРАВЛИЧЕСКИХ ПРЕОБРАЗОВАТЕЛЕЙ АВИАЦИОННЫХ ДВИГАТЕЛЕЙ
Authors: Кононыхин Евгений Александрович , Епифанов Сергей Валериевич
Published: August 2019

The main trends in the use of aircraft engines actuators, that convert electrical commands into mechanical and hydraulic, are presented. Examples of the use of modern engine control systems are described, in which hydraulic cylinders are used to move the actuators. The hydraulic commands for moving hydraulic cylinders are formed by electro-hydraulic converters. A significant increase in the modern engines mechanization complexity required an increase in the reliability of electro-hydraulic converters and the level of static and dynamic characteristics. The necessity of introducing a new generation of electro-hydraulic converters into the control systems of domestic aircraft engines is discussed. The analysis of the list and method of determining indicators using which it is advisable to control the balanced conformity of the design to the technical requirements at the design stage is carried out. A model-oriented approach to the design of electro-hydraulic converters is described. The structure of a universal model of the working process of an electro-hydraulic converter is proposed. A feature of the model is the predominant use of the geometric parameters of the elements and properties of materials as initial data. The main constituent elements of the working process model are the models: an electromechanical converter with an elastic part, a preliminary stage, orifices, volumes of compressible fluid and attached masses. The main parameters of the actuator, external parameters (defined in the technical requirements for the whole product) and internal parameters (characteristics of the hotel units) of electro-hydraulic converters are highlighted. The analysis of the dependence of external and internal parameters and the parameters of the actuator. The design method of electro-hydraulic converters is given. A key feature of the method is the use of a workflow model at almost all stages of design. To form a balanced combination of parameters of the electro-hydraulic converter in the structure of the method, it is proposed to use the objective function, which includes the internal parameters of the electro-hydraulic converter.
ОЦЕНКА РЕЗУЛЬТАТИВНОСТИ И ЭФФЕКТИВНОСТИ ПЛАНИРОВАНИЯ В СИСТЕМЕ МЕНЕДЖМЕНТА КАЧЕСТВА ПРЕДПРИЯТИЯ-РАЗРАБОТЧИКА АВИАЦИОННОЙ ТЕХНИКИ
Authors: Назаренко Юлия Александровна , Степаненко Сергей Михайлович
Published: August 2019

It is considered the role of planning in the quality management system of an enterprise from the standpoint of the international standard ISO 9001: 2015. The company should plan both the functioning of the quality management system itself and the production processes directly to ensure the required quality of the supplied products or services. The ISO 9001: 2015 standard also provides for mandatory monitoring and measurement of the planning process for continuous assessment of the functioning and effectiveness of the quality management system. The approaches to the analysis of the effectiveness and efficiency of the planning process when creating aircraft engines in the overall quality management system of the enterprise are considered. The general approach to evaluating and analyzing efficiency has been analyzed. It is noted that the efficiency analysis should determine the degree of implementation of the planned activities, as well as the degree of achievement of the planned results. Measuring the effectiveness of planning, as a measure characterizing the ratio of the output of the process and costs (resources, finance, time, etc.) incurred to achieve results, should be based on a comparative analysis of the economic activities of the enterprise related to the achievement of goals set out in the plans. In the general case, the evaluation of the effectiveness of the planning process should be carried out with the direct participation of both the units performing the tasks set in the plans and with the participation of the planning and economic units of the enterprise. It is noted that the evaluation of the effectiveness of the developed plan's implementation should be carried out in three main areas: the effectiveness of the implementation of each of the individual projects; the degree of strategic goals achievement; the degree of compliance of the goals with the interests of stakeholders. To promptly respond to the planning process to improve it, it is proposed to use rapid assessments based on indirect indicators: comparing the actual number of completed plan items and spending time and resources for their implementation in the design departments. Examples of the effectiveness and efficiency analysis of the planning process are given.
ПОКАЗНИКИ СІРКОВОДНЕВОЇ РОТОРНО-ПОРШНЕВОЇ РОЗШИРЮВАЛЬНОЇ МАШИНИ У СКЛАДІ ЕНЕРГОТЕХНОЛОГІЧНОЇ УСТАНОВКИ
Authors: Ткач Михайло Романович , Тимошевський Борис Георгійович , Митрофанов Олександр Сергійович , Проскурін Аркадій Юрійович , Галинкін Юрій Миколайович
Published: August 2019

The article discusses the efficiency of applying a 12RPE-4,4/1,75 rotary-piston engine as an expansion machine for a promising energy technology plant for the production of hydrogen sulfide from the depths of the Black Sea. In this installation, high-pressure hydrogen sulfide is used in the expansion machine to produce mechanical energy, which can ensure the operation of pumps and other equipment. 12RPE -4,4/1,75 is a 12-cylinder short-stroke engine with an S/D ratio of 0.4. A feature of the engine is that for the distribution of the working fluid are used inlet and outlet openings, the overlap of which is carried out by the central rotor. Thus, the central rotor performs the function of a slide valve and a housing in which the pistons move. The use of the spool distribution provides a simple and compact design. The pressure of hydrogen sulfide at the inlet to the rotary-piston expansion machine is determined in the range of pipeline immersion depths of 0...1000 m, at a temperature of 280 ... 285 K and gas content of hydrogen sulfide in seawater 0.0...10.0 m3/m3. The definition of the main parameters of the working fluid and the working process is performed for a daily production of seawater of 100 m3/day. It is calculated that for a gas content of 2.5 m3/m3 with a depth of immersion of the lifting pipeline H = 250...1000 m, the power of the expansion machine is 0.20...0.61 kW, for gas content 5 m3/m3 – 0.65...0.86 kW for gas content 7.5 m3/m3 – 1.20...1.87 kW, for gas content 10 m3/m3 – 1.65...2.55 kW. Indicator diagrams of the expansion machine operation depending on the gas content of hydrogen sulfide in seawater and the depth of immersion of the pipeline were obtained. It was determined that with an increase in pressure at the inlet, the effective efficiency of the hydrogen sulfide expansion machine lies within 0.21...0.49. Also, with an increase in inlet pressure, the specific effective consumption decreases from 51.5 to 25.17 kg/kWh. Low values of specific effective consumption of hydrogen sulfide and high values of effective efficiency are due to the design features of the rotary-piston expansion machine, which combines the advantages of the piston and rotary engines.
ОПРЕДЕЛЕНИЕ КОЭФФИЦИЕНТА КОНВЕКТИВНОГО ТЕПЛОПЕРЕНОСА В ГИДРОАККУМУЛЯТОРЕ С ТЕПЛОВЫМ РЕГУЛИРОВАНИЕМ ДЛЯ УСЛОВИЙ НЕВЕСОМОСТИ
Authors: Коваль Полина Сергеевна , Решитов Эдем Русланович , Турна Рустем Юсуфович
Published: August 2019

In the modern world with the increasing power of spacecraft heat dissipation, the need has arisen to use efficient heat removal systems with two-phase heat transfer contours. Their advantages are determined by the fact that they can carry a much larger amount of heat per unit of consumption than when using a single-phase coolant. The energy consumption of the pump for pumping the coolant is insignificant, and the use of heat exchange during boiling allows you to maintain the temperature of objects almost the entire length of the circuit close to the saturation temperature. All heat transfer processes occurring with a change in the state of aggregation of a substance (boiling, condensation) occur much more intensively than during convective heat exchange in a single-phase liquid. A feature of this system is the change in mass of the coolant in the circuit when changing the operating modes of the two-phase heat transfer system. To regulate the amount of coolant in the circuit, as well as to maintain a predetermined pressure (boiling point), a hydraulic accumulator with thermal regulation (HCA) is used. The actual processes of heat and mass transfer in HCA are non-equilibrium, which complicates the calculation of the thermal control system. This paper describes the concept of a nonequilibrium mathematical model for calculating heat and mass transfer processes in HCA. It is shown that the nonequilibrium of processes can be taken into account by the convective heat transfer coefficient “k” in the mathematical model of HCA: k = 1 corresponds to the absence of convection; k > 100 corresponds to an equilibrium process. Based on the analysis of the flight space experiment for heating HCA, a prediction was made of the value of the convective heat transfer coefficient k under zero-gravity conditions. To assess the influence of the “k” value on the process of regulating the two-phase heat transfer contour under weightless conditions, it is recommended to use the values k = 30 ± 15. In ground-based experiments at high-intensity convection in HCA, processes are much more equilibrium than in zero gravity. It is concluded that the equilibrium process (high values of k) can be considered as more conservative concerning the regulatory process in weightlessness.