2013. № 64

Now experimental studies of damper effectiveness for overhead power supply systems play a key role in the power dissipation analysis. But the mathematical models are of interest as well, allowing not only to calculate the damper dynamic characteristics, but also to optimize their design parameters in order to increase the dissipation effectiveness in the widest frequency range.
Spatial vibrations are modeled for a system consisting of a flexible elastic rope and weight (solid), rigidly attached to one rope end. The problem is solved with a full account of the stiffness and inertial characteristics of the system. The energy dissipation takes into account, which has a pronounced hysteresis type. The equations are obtained in geometrically linear formulation. Further studies involve the use of non-linear dynamic equations using the deformation equations in the quadratic approximation and physical relationships considering the hysteresis losses.

Keywords: vibration damper; natural frequencies and mode shapes; nonstationary vibrations; energy dissipation of the hysteresis type; kinematic approach

This article is about theoretical research results of behavior of free cavern bounds, created behind the body in high speed fluid flow by hydrodynamic characteristics. In practical tasks such characteristics are usually ring wings with proper profile in section. It has been shown, that usage  of ring vortex characteristics and numerical method of solving Navie-Stokes equations using Flow Vision it is possible to create a cavern with bounds in specified limits.

Keywords: cavity; model; ring wing; numerical method

Тhе paper presents the some results of theoretical and experimental research of axisymmetric cavity streamline of the lengthen bodies in vertical stream. These streams are known as Lighthill-Shushpanov flows. The results of the testing have been cited as an example  of the new method of the cavity formation for the lengthen bodies in vertical stream.

Keywords: cavity; vertical flow; ring wing

The paper presents the results of numerical studies of the effects of spinner shape, relative size of hub and the diffuser on the characteristics of axial fans. Obtained the coefficients of of the total pressure, productivity efficiency and power factor.Shows the influence of the spinner shape and relative size of hub on the characteristics of the fans.

Keywords: axial fan; spinner shape; relative size of hub; the Reynolds-averaged Navier-Stokes equations; coefficients of the total pressure; performance; efficiency; power factor fan

Feasibility of long duration flight UAV, using solar energy in Russian territory is considered. The main parameters of such vehicles for flight in different region of Russia are determined.

Keywords: solar powered aircraft; photovoltaic cell; continuous flight

At present, humanity has managed to look into the depths of our lunar satellite to a depth of 3 meters. Perhaps only by drilling on celestial bodies, first of all automatically - without human intervention, to answer the question of the laws of planetary evolution, in which the origin of life is either a product of a local accident or the result of yet unknown causes. As the development of space bodies challenges extraterrestrial drilling will inevitably become more complicated. Need drilling to depths of hundreds of meters to study the spread of frost on the surface of some planets and satellites, to find, for example, water, for seismic, biological and other studies. Drilling may be necessary during the construction of lunar bases. There is a project for the construction of a lunar base with deep well, a few tens of meters at the bottom which will be blown up charge of high power. This forms a spherical cavity, it is suitable for the equipment of the shop, secure layer of lunar soil from large changes in temperature and cosmic radiation. These works will require a penetrators fired from landers space probes and penetrates the soil to a considerable depth at a relatively low curb weight.

Keywords: penetrator, lunar soil, the solid fuel rocket motor; drilling

In the article the ground of application of methods and devices is conducted for providing of safe terms of realization of stand tests of motive options and their systems on a high-efficiency fuel pair lotwo and hydrogen. The questions of safety of working off and exploitation of the space systems are considered, advantage of application of restoration chart of reheat of generator gas is shown in engines working on the condensated natural gas and lotwo, with the ground of charts, parameters and optimal multipleness of the use of them in the objects of multiple space systems.

Keywords: motive setting; reheat; safety; exploitation; emergency situation; system

The questions of simulation of working process in a supersonic ramjet engine working on aviation kerosene are considered. The computed examples of performances for one scheme of a supersonic ramjet engine are given.

Keywords: flight vehicle; combined power plant; supersonic ramjet engine; mathematical simulation

In article the substantiation of structure and quantitative values of indicators of reliability of system of gas supply of a technical complex is spent. The mathematical model of reliability of system of gas supply of a technical complex taking into account possibility of restoration of an efficient condition after refusal in the course of performance of works is considered.

Keywords: reliability; system of gas supply of a technical complex; mathematical model; probability of non-failure operation

Technical systems reliability ensuring tasks on operational stage are considered.
Probabilistic-cost parameters forecast algorithms on product maintenance process are given.
Technical systems resource rationing methods allowing for planned preventive maintenance, emergency and planned replacements are presented.
Presented results can be useful to technical systems operation specialists and corresponding profile students.

Keywords: reliability; resource; maintenance periodicity

The paper presents the results of a comparative analysis of computer simulation to determine the characteristics of advanced high-pressure fan with swept blades H-1 and fan TsAGI OV-23. The influence of the number of blades on the mass flow - dynamic pressure characteristics and the coefficient of efficiency of axial fans H-1 and OV-23 has been analyzed. Shows the advantages of the fan with blades forward-swept over the fan TsAGI, expressed in increasing the efficiency and expansion of its range of stable work with equal dimensions and angles of blade setting. Presented by the explanation physics of the phenomenon increase the stability of an axial fan with blades forward-swept towards of flow separation.

Keywords: Axial Fan; Fan Blade Forward-Swept; the Reynolds-Averaged Navier-Stokes equations; the Method SIMPLEC; the Coefficients of the Total Pressure and Productivity Efficiency and Power Factor of the Fan

The article presents the dependence of the stress concentration in the loop holes in the polymer composite material from the geometrical parameters of the rows of holes.

Keywords: composite polymer; hole; stress concentration; finite element method