Vol 4, No 1 (2018)

Cover Page

Full Issue

Articles

Influence of vibrations on characteristics of hydromechanical regulators

Gulienko A.

Abstract

The main noise source in gas distribution systems is the gas pressure reduction in regulators. Nowadays the special mufflers, representing a set of orifices, are widely used for pressure regulator noise reduction. However, the installation of such devices may cause malfunction of the unit. That is why there is a need to study the characteristics of regulator with the muffler in order to select the parameters at which the desired pressure reduction is retained and the noise is reduced.
This paper studies the regulator which represents an equivalent of reduction valve of a similar scheme with the muffler installed in the outlet line. The output impedance increase may lead to loss of stability and control accuracy. The mathematical model of this system was implemented in the Simulink software in order to analyze the muffler impact on pressure relief valve static and dynamic characteristics. The program in Matlab software was also developed for determination of the noise generated by the system. The experimental research using the pneumatic bench was carried out for mathematical model verification.

Journal of Dynamics and Vibroacoustics. 2018;4(1):6-15
pages 6-15 views

Constructive actions for decrease in acoustic loading in the assembly and protective block 81ks

Popov P., Igolkin A.

Abstract

On the basis of the experimental works which are carried out in TsAGI laboratories necessary parameters of coefficients of mechanical losses, absorption coefficients, coefficients of distribution and sound insulation for composite samples with drawing on their surfaces of different sound-absorbing materials which have allowed to reduce loading on adaptable spacecraft to the total mean square level of the acoustic pressure which is not exceeding 140,6 dB are received. In work the rated scheme of research of decrease in acoustic loadings is given and comparison of theoretical and experimental data is given. Results of rated pilot studies have been confirmed with design tests of launch vehicle "Soyz-2".

Journal of Dynamics and Vibroacoustics. 2018;4(1):16-20
pages 16-20 views

Model and finite element methods for studing insulating lining of space module compartments

Popov P., Kuznetsov A., Igolkin A., Murtazin V.

Abstract

At design of the space-rocket equipment the prediction problem of acoustic action on elements of the launch vehicle design and payload. The sources of such impact are the engines operating at the start and the incoming air flow acting on the launch vehicle at the start and on the active part of the flight in the earth's atmosphere. However, the solution of the problem, complications of the impossibility of testing in bench conditions. Check the adequacy of the selection process only when the launch vehicle. Therefore, it is important to develop a methodology for calculating the minimum sound insulation based on the physical parameters of the material and the geometric parameters of the structures. The calculation of these parameters was carried out on models of structures, in connection with which the proposed approach was called model. The simulation is carried out by the finite element method while simplifying the initial structure to a similar rigidity. The results were compared with experimental data.

 

Journal of Dynamics and Vibroacoustics. 2018;4(1):21-26
pages 21-26 views

Evolution of the fan casing treatment design of the counter rotating turbofan with the purpose of increasing its acoustic performance

Pochkin Y.S., Khaletskiy Y.D., Mileshin V.I.

Abstract

The results of an experimental study of the effects of several slot type casing treatment (STCT) configurations on ducted counter rotating fan model (DCRF) noise are given in present work. The casing treatment design parameters such as lattice duty cycle and the cavity height were varied. It is shown that the most important parameter is the duty factor of the lattice. The configuration of STCT, which provides the greatest reduction of sum sound power level of the fan model was installed over the second rotor only and had the highest duty factor.

Journal of Dynamics and Vibroacoustics. 2018;4(1):27-35
pages 27-35 views

Determination of the frequency characteristics of a magnetorheological elastomers vibration control platform

Bazinenkov A.M., Makeev I.V., Rotar` A.P., Ivanova D.A., Mikhailov V.P.

Abstract

To reduce the effects of external vibration disturbances, various methods of vibration protection are used, including active, semi-active and passive vibration isolation systems. For vibration isolation of modern precision equipment, it is proposed to use a plate-like vibration isolation based on magnetorheological elastomers. Studies of the frequency characteristics of this platform and its management capabilities are necessary to determine the effective modes of operation of the platform. Thanks to the tests on the vibration electrodynamic installation, the dependence of the coefficient of transfer of the amplitude of vibration displacement on the oscillation frequency at different currents was obtained and showed that the effective range of vibration isolation is from 38 to 100 Hz.

Journal of Dynamics and Vibroacoustics. 2018;4(1):36-40
pages 36-40 views

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