Vol 1, No 2 (2014)

Cover Page

Full Issue

Articles

Modernization of automatic control system for LNG mainline gas turbine locomotiv

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Abstract

The article is concerned with modernization of automatic control system for mainline gas turbine locomotive GT1h-001 with a gas turbine engine NK- 361, working on liquefied natural gas (LNG). It contains dynamic response analysis of original and modernized automatic control system, justified structural adjustments of automatic control system and fuel system, and test data for gas turbine locomotive.

Journal of Dynamics and Vibroacoustics. 2014;1(2):13-19
pages 13-19 views

Dynamic mathematical model of the lubrication system

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Abstract

The object of research is the lubrication system with supply and scavenges oil gear pumps with electric drives. Analyzed the features of the workflow in aggregates lubrication systems, and evaluated the possibility of applying a homogeneous model for the description of a two-phase mixture of "oil foam". It describes the principles of construction of mathematical model of the lu- brication system based on dynamic equations of the typical processes in the nodes - flow of two-phase mixture, mixing air and liquid flows, filling cavities of the pinion pairs in the suction side of the pump. Verification of the devel- oped mathematical model is made by comparing the calculated and experi- mental processes.

Journal of Dynamics and Vibroacoustics. 2014;1(2):24-33
pages 24-33 views

Research of dynamics of the design of compartments of the rocket-carries at cross-section pseudo-acoustic loading

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Abstract

In given article the method of a finding of the vibrating response of a design of compartments of the carrier rocket is described, the given method has been approved on concrete separate constructive zones, the comparative analysis with results of flight design measurements is carried out.

Journal of Dynamics and Vibroacoustics. 2014;1(2):20-23
pages 20-23 views

Modeling of electro-hydraulic controlled propulsion system

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Abstract

Modern rocket propulsion system is a dynamic system with a set of inter- connected links Modern controlled propulsion system, ensuring in the pro- cess of its operation on the aircraft receiving the given basic characteristics. Main propulsion controlled variable serving as controlled object is second mass flow of gases through the nozzle. Regulating influence area is man- aged throttle hydraulic adjusting the surface area of solid fuel combustion by draining the channel charge. Currently achieved level of development of computer technology allows to simulate the behavior of the object and its management systems. This helps improve the design quality and reduce de- bugging time hydroelectric generators.

Journal of Dynamics and Vibroacoustics. 2014;1(2):34-39
pages 34-39 views

Comprehensive solution of machine dynamics and vibroacoustics problems

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Abstract

The following items are presented in the work:
Developed with the author's direct participation methods and techniques of comprehensive solution of machine dynamics and vibroacoustics problems. Extensive information on vibration suppression processes in pneumatic- hydraulic systems, suppression of vibrations and noise in systems of aerospace products and ground process units.
Samples of successfully solved tasks on protection of the products against pressure oscillation, vibrations and noise.
Journal of Dynamics and Vibroacoustics. 2014;1(2):4-12
pages 4-12 views

Research communication of hydraulic and vibroacoustic characteristics of hydrodevices traffic control systems

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Abstract

The influence of fluid flow and pressure drop in the level of vibrations in continuous operation windows opening electrohydraulic amplifier (EHP). It is shown that the vibration level is determined by the speed of its flow in the windows of the EHP. At speeds greater than the critical value, its impact on the level of vibrations is negligible. Changes in the level of vibration signifi- cantly to the differential pressure of 2,94 MPa, with a further increase in its level of vibration is changed slightly. It is also shown that a high air content in the liquid leads to the formation of transonic flow of the working fluid with increased vibroaktivnosti hydraulic devices.

Journal of Dynamics and Vibroacoustics. 2014;1(2):40-45
pages 40-45 views

Numerical modelling of tonal components of pressure pulsation spectra in the LRE booster turbopump screw stage

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Abstract

Booster pump unit providing the required NPSH for the main LRE turbopump feed system operates in high vibration activity. Numerical simu- lation of unsteady flow in the booster pump unit allows one to analyze the amplitude-frequency characteristics of pressure pulsations generating the pump casing vibration. The obtained results were analyzed, the signals of pressure pulsations at the inlet and the outlet of the pump screw rotor ob- tained. The sources of pressure pulsations are defined. The conducted com- putational experiment revealed the direction of work to reduce the influence of hydrodynamic sources of vibration on the total vibration level of booster pump unit.

Journal of Dynamics and Vibroacoustics. 2014;1(2):46-49
pages 46-49 views

Numerical simulations of dynamic loads in aviation combined pumps

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Abstract

Modern cryostatting systems find important applications in power and space transportation systems. The cryostatting system is a closed hydraulic loop for the thermal management and control of thermal modes of supercon- ducting cable lines, cryogenic rocket and space units fuel tanks. The working medium is liquid nitrogen. One of the main components of such a system is the criorefrigirator. In the criorefrigirator compression scheme is used with following expansion of neon in the turboexpander, machine with gas-static bearings. Urgent task in the design phase is to determine the pressure fluc- tuations in the flow of the turbo expander and dynamic loading of the struc- ture. This paper presents the numerical simulation of unsteady gas-dynamic processes in the turbo expander radial turbine flow. Expansion turbine con- sists of mounted on the same shaft the radial turbine impeller and centrifugal compressor first stage, that also serves as a gas-dynamic brake. Gas is fed to the expander casing through two pipelines. Further, it is accelerated in the nozzle cascade and enters the turbine impeller blades. After expansion and reduction the temperature, the exhaust gas passes through the axial diffuser. Rotor speed is 25,200 rev / min. The geometry of the computational domain is developed in order to capture the main features of the flow in the working fluid cavity, including the geometry of fourteen working blades and eight vanes of the nozzle cascade. The computational domain is divided into three subregions: the casing of the nozzle cascade, rotor and exhaust part. The problem is solved with the use of so-called sliding surfaces which serve for transmitting the data from the rotor, where the calculation is carried out in a rotating coordinate system into the stator zone accounting an angular dis- placement and sub-grid interpolation. Time step chosen from the condition to ensure the angular displacement in one time step within a single cell of the computational grid. The instantaneous velocity, pressure, temperature and Mach number fields are obtained with calculations. Few points in the nozzle vane channel oblique zones are selected to fix pressure pulsations. The spectral analysis of the data reveal that the tonal component with blades passing frequency dominates the spectra of pressure pulsations, its ampli- tude is above 7000 Pa. Calculation of loading on nozzle blade gives the am- plitude of force 2 N and amplitude of momentum 0.03 N m

Journal of Dynamics and Vibroacoustics. 2014;1(2):50-55
pages 50-55 views

Comparative analysis of pressure pulsations in tubular guide channels of the LRE screw centrifugal pump

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Abstract

Application of tubular guide channels allows to smooth the pressure pulse due to the rotor blade passage, reduce the amplitude of pressure pulsations and vibra- tions, as well as significantly improve the dynamic strength of the structure. The mechanism of reduction of pressure fluctuations and vibration of the pump cas- ing when using tubular channels guide unit is explained. Urgent problem is the numerical simulation of unsteady flow in the pump outlets to assess options and make their optimization. Computational analysis was performed using the meth- od of "sliding grid". The calculation results and comparative analysis of variants of the guiding unit of the high-speed screw centrifugal pump are outlined. In the computational experiments are determined signals and spectra of pressure pulsa- tions at different points of the pump outlet path, energy parameters and energy loss in the pump outlet path.

Journal of Dynamics and Vibroacoustics. 2014;1(2):56-62
pages 56-62 views

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