Vol 5, No 2 (2019): 21.06.2019
- Year: 2019
- Published: 21.06.2019
- Articles: 5
- URL: https://dynvibro.ru/dynvibro/issue/view/398
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Description:
опубликован 21.06.2019 г.
Full Issue
Articles
Study of the effect of the diameter of the case of the safety valve on his hydraulic resistance coefficient
Abstract
The article discusses the dependence of the parameters of the safety valve on the geometry of the flow part. Direct-action single-stage safety valve is selected for the study. The influence of its case diameter on the hydraulic resistance coefficient was researched. A computational experiment was conducted using the Ansys Fluent software package. As a result, it is found that when the ratio of the plate diameter to the saddle diameter is 1.3 then a decrease of the body diameter to a value less than two diameters of the saddle is resulting in a significant increase of the coefficient of hydraulic resistance
6-10
Mathematical modeling of changes in geometric parameters of pneumatic muscles
Abstract
Today, this type of drive as pneumatic muscles has wide application. Pneumatic muscle is a one-way drive and has such advantages as the developed force, as well as speed. Pneumatic muscles, compared to pneumatic cylinders, have a non-linear structure that needs to be correctly identified. In this paper, we study the dynamic processes of pressure change in the working cavity of a pneumatic muscle in order to build a mathematical model, which can later be used to develop control systems, where the main actuator is pneumatic muscle, as well as to accurately describe and predict the geometric parameters of pneumatic muscles on pressure of compressed air in the working cavity.
11-17
About improvement of the scheme of correction of frequency characteristics of probes for measurement of pulsations of pressure in gte
Abstract
It is known that pressure pulsations affect the performance of power plants, including a gas turbine engine, reducing the reserve of gas-dynamic stability of the compressor, creating conditions for oscillatory combustion in the combustion chamber. When fine-tuning the engine in the context of the pressure pulsations there is need for measuring means working at extreme temperatures and vibrations. The most acceptable of these means is a probe consisting of a supply waveguide, a pressure pulsation sensor and a corrective element in the form of a long line. However, in the low frequency region there is an uneven amplitude-frequency characteristic of the probe, due to the influence of the reflected pressure waves from the closed end of the long line. It is proposed to install an acoustic RC-filter with resistance equal to the wave resistance of the long line at the output of a long line. The paper theoretically shows that such an improvement of the probe allows to expand the frequency range of measurement of pressure pulsations. The material of the article will be useful for specialists who develop and use tools for measuring pressure fluctuations in extreme conditions, for example, when developing gas turbine engines.
18-25
Method of calculation dynamics roller bearings pinion differential gear
Abstract
In this paper, the method of calculating the dynamics of roller bearings of satellites of differential turbo-screw reducers is briefly considered. The distribution of forces on the rolling elements is found and their durability on the contact stresses. Determines the thickness of the lubricant layers in the contacts of the rolling elements with the rings of with the separator jumpers, as well as in the contact of the separator with the centering surfaces of the bearing rings; determines the sliding speed in the contacts and, as a consequence, assess the danger of jamming.
26-36
Experience of application of technological processes for ensuring the constructive reliability of units
Abstract
The article proposes measures to improve the reliability and durability of the units under non-standard operating conditions, consisting in the simultaneous introduction of various technological processes and design solutions.
37-42