Vol 16, No 4 (2017)

High-power shock, heat, mechanical and – especially – acoustic loads present a serious problem as their impact on the rocket and the launch pad can be too strong. Turbulent supersonic jets ejected from the vehicle nozzles are the main source of these loads. One way to reduce the intensity of acoustic loads is to supply a special system of water jets that interact with the supersonic gas jets near the rocket nozzles. Numerical simulation of this interaction is an important part of the design of such noise reduction systems. The proposed numerical model should enable simulation of various processes of different scale, such as gas/droplets interaction, nozzle jets in the near field, acoustic loads in the far field, chemical reactions and others. Therefore, such a model should be modular and hierarchically aligned. A flexible and extensible implementation of the numerical model can be possible with open-source codes. This paper concerns the problem of numerical simulation of compressible turbulent supersonic jets. The hybrid gas dynamics solver which was used in this investigation is one of the main modules of the general numerical model. Preliminary results of verification of this module are presented. Comparison of numerical and experimental results for various experimental cases, both Russian and foreign, is given.

Spatial resolution is one of the most important characteristics of a radar image. Significant limitations in communication regulations should be taken into account concerning radar facilities in long-wave frequency ranges (P or VHF). These limitations do not allow high resolution of a radar facility. The article presents a possible conceptual design of a small spacecraft with a bistatic dual-frequency P-VHF radar facility. The system under consideration is characterized by the displacement of the transmitting station in the process of imaging and stationary position of the receiving station. The synchronization of the system is ensured by organizing a direct channel of signal propagation between the transmitter and receiver. The distinctive feature of the system is simultaneous radiation of direct impulses of the space-borne radio transmitting device in two bands. The influence of the atmosphere on the radar resolution is compensated as a result of joint processing at the ground receiving station. It is expected that total spatial resolution can be brought up to 2 meters due to the simultaneous operation in dual-frequency ranges. The results of a full-scale ground-based experiment simulating the work of the proposed radar complex are presented in the article.

The paper presents an analysis of the peculiarities of operation of gas-turbine engines with an afterburner. The main shortcomings of the existing afterburners are described.  The structural design of afterburners is analyzed. It is shown that the existing afterburners do not provide efficient control of the working process throughout the operational range of heights and speeds of flight. Methods of calculating the parameters of the working process organization in the afterburners are specified. The necessity to control the place and the angle of supply of fuel upstream of the flame stabilizer is proved. New operating factors are proposed for the system of automatic control of the afterburner. The use of new structural designs of collector devices incorporated in the afterburner is justified. These devices allow efficient control of the organization of the working process in them throughout the operational range of heights and speeds of flight. The classification of afterburners is specified and the advantages of gas-turbine engines incorporating afterburners with adaptive fuel supply collector devices are justified. 

The article discusses the technological development of Russia in the light of the tasks set by the National Technological Initiative. The subject of discussion and analysis is the logic of the development of the innovation ecosystem of the Russian Federation, the problem of anticipating the world trends in technical and economic development and the global issue of the grounds for making state decisions in the spheres of science, economy and education. It is shown that solving the task of developing a technological innovation ecosystem requires involvement not only of managers and specialists in engineering development, but also philosophers, sociologists, historians. The purpose of the article is to show the transformation of the technical and economic balance of society, inevitable in the conditions of explosive technological growth, to isolate and analyze the basic stages of this transformation, their philosophical foundations and main features. The question of the development of a technological innovation ecosystem in terms of general philosophy is stated as a problem of constructing ontologies that entail significant technological, economic and social transformations. The trial solution of the problem is represented in the form of a scheme of eight stages of development – from the model “Funnel” to the model “Grail” – and is a deductive construction, open to verification and falsification procedures. Verification and approbation of the solution of the problem of the development of technical and economic balance formulated in the article requires the participation of a wide range of specialists in the socio-humanitarian, technical and natural-science fields. The current state of technology and economics on a global scale is characterized as a transition from “second nature” technologies to “third nature” technologies. A consistent model of management of the technical and economic balance, overcoming the current model described by the Stevens-Burley formula is demonstrated. The role and the problem of the person in the conditions of technologies of the second and third nature is emphasized, problems of determining the substance of educational activity concerning the generations that will live in a new technical and economic environment are formulated.

The article deals with the design of an advanced throttle valve with an elastic tubular element designed to reduce the vibration and noise of hydraulic systems upon which strict requirements for vibro-acoustic characteristics are imposed. The analysis of known similar devices is carried out and the design of the throttle valve is justified. A detailed analysis of the strained state of the elastic tubular element is performed and the relationship between the deformations of this element and the hydraulic parameters of the working medium in the flow part of the valve is shown. The experimental flow characteristics of the valve under study are analyzed. The analysis made it possible to identify the parts of the characteristics at which the flow rate remains constant when the pressure differential across the valve changes. This feature of the hydraulic characteristics of a valve with an elastic element is substantiated. Ways of further directions of the prospective valve research are shown.

Improvement of methods of radiometric correction for multichannel spectral hardware and wide usage of LED-sources require the development of both mathematical and experimental methods of calibration of the obtained spectral data. To obtain true coefficients of spectral reflection it is necessary to use high-stable radiation sources, which makes it possible to improve measuring accuracy, to perform a transition from absolute to relative units of measure. Application of high-brightness LEDs for the purposes of radiometric calibration is limited by variations of their characteristics over time, degradation of structures and temperature drift of characteristics. To stabilize the spectral LED radiation maximum we need to resort to additional methods for the temperature control of radiation sources by controlling dissipation power on the crystal, taking into account high nonlinearity of the dissipation curve of the crystal depending on the passing current. The nonlinearity of the processes of the crystal heat release at the optimum operation point calls for the application of a high-precision mode of temperature control. A technique of “proportional integral-derivative” temperature control for light-emitting diodes of increased brightness with phosphor-coated crystals was developed and experimentally tested. The possibility of using temperature control of a highly stable source to stabilize spectral characteristics is shown. It allows using this technique to increase the accuracy of assessing the optical properties of the surface under investigation.

The paper presents solutions to the problems of estimation, analysis and forecasting of indicators of reliability, survivability and efficiency of on-board equipment (BE) of small satellites (SS) in standard and specified conditions of operation. A distributed software complex for multi-criteria evaluation, analysis and prediction of the values of reliability and survivability indicators of SS BE was developed taking into account the factors of outer space, as well as control of their reconfiguration at different stages of the life cycle (SPIIRAS). The developed complex of methodologies and software tools for estimating the reliability of SS BE (UIIP) was integrated as a distributed segment into the SPIIRAS software complex. The developed software systems are based on using the applied control theory of structural dynamics of complex objects, as well as the developed methods of estimation, analysis and forecasting of indicators of reliability, survivability and efficiency of SS BE, and database mining approach.

Approaches to accomplishing functional control of field-programmable gate arrays (FPGA) are described. The first part of the article describes the existing equipment that allows conducting functional tests of FPGAs. A table comparing the main parameters of the equipment available in the market is given. The table contains the main parameters of the equipment that make it possible to simplify the process of conducting functional tests of FPGAs. The main advantages and disadvantages of using this equipment are shown on the basis of the analysis. In the second part of the article the author describes the main methods of conducting functional tests of FPGAs. When developing algorithms, the author divides all the internal structure of a FPGA into two functionally independent parts. The first part is the internal programmable logic, and the second part contains functional blocks built into a FPGA. The article gives examples of algorithms developed on the basis of the methods described and configuration firm-ware produced with the help of these algorithms. The developed algorithms carry out functional control of the internal logic, as well as of function blocks built into a FPGA. To develop algorithms for functional control of internal logic the author uses the method of iterative logic arrays. A method of creating built- in self-test structures is used for the control of function blocks built into a FPGA. In the final part the author draws conclusions and describes the directions of his further research.