- TITLE:
THE ANALYSIS OF INTERACTION OF INERTIA FORCES AND MASS FORCES WHICH HAVE MAGNETIC NATURE IN UNSTABLE MECHANICAL AND BIOLOGICAL FLOWS
- AUTHOR(S):
A.N. Mamedov, S.V. Stas, Ya.A. Honcharova, O.M. Yakhno
- ABSTRACT:
As we known, unstable flows in the field of inertia due to convective acceleration and viscous
friction are widely used in hydraulic systems. But in the same time, the bad studied flow of
electrically conductive liquids remains under conditions when an additional effect on the flow forces
with a magnetic nature arises a flow in the cross section. Essentially relevant and insufficiently
studied problem is the behavior of liquids in the initial section, which has the following forms. Shown
that in the absence of inertia forces from convective acceleration (in the Stokes flow) the velocity
diagram depends only on the rheological properties of the fluid.
In this work we identifies the conditions under which the magnetic field contributes to the
inhibition of the flow in the channel; Cases where the fluid exhibits an anomaly are considered and
data on the determination of the velocity and stress fields are obtained. Physical modeling was
carried out using capillary viscometers of various diameters. Rheological studies have shown that
the fluids which were in use can be described by the laws of Newton, Ostwald-de-Ville and Ericksen.
Keywords:
inertia forces, magnetic field,
viscosity, initial section, pressure,
velocity field
© 2019 Journal of the Technical University of Gabrovo. All rights reserved.
- PAGES:
36-
- DOWNLOAD:
THE ANALYSIS OF INTERACTION OF INERTIA FORCES AND MASS FORCES WHICH HAVE MAGNETIC NATURE IN UNSTABLE MECHANICAL AND BIOLOGICAL FLOWS
- TITLE:
ON THE USE OF WATER-ICE JETS IN THE PURIFICATION OPERATIONS OF TURBINE UNITS
- AUTHOR(S):
Vitalii Tkachuk, Oleksandr Salenko, Viktor Schetinyn
- ABSTRACT:
The paper deals with the use of water-jet means for cleaning operations of turbine units. To
activate the process and improve the quality of purification, it is proposed to use a water-ice jet
formed by mixing a water jet with a cryogenic liquid (liquid nitrogen). At the same time, the factors
that influence the efficiency of ice formation, the size of ice floes and their ability to perform the work
of destroying layers of pollution are analyzed. Models of formation of water-ice jet are developed
and regularities of its influence on the surface are established. The influence of the conditions of
formation of a water jet on its cleaning ability is revealed. It is shown that along with the flow of
cryogenic fluid, in particular liquid nitrogen, the geometry of the mixing chamber has an important
influence. Thus, the position of the point of introduction of nitrogen into the cavity of the chamber
determines both the amount of ice formed and the size of the particles. The farther the nozzle slice,
the larger the particle size of the ice forms. Fractograms of the generated ice flow were also
obtained and their functional conditionality was determined by the modes of generation and the
parameters of the mixing chamber. Multiple factorial planning of the experiment was performed and
dependencies were obtained to establish technological modes of processing. Using surface model
reproduction tools, it is shown that the use of water-iced jet not only improves the environmental
friendliness of the method, but also provides the highest quality surface cleaning without changing
the parameters of microgeometry.
- PAGES:
32-
- DOWNLOAD:
ON THE USE OF WATER-ICE JETS IN THE PURIFICATION OPERATIONS OF TURBINE UNITS
- TITLE:
NEW DESIGN OF COMBINED ELECTRIC MACHINES TO INCREASE THE EFFICIENCY OF PROCESSING COMPOSITE MATERIALS
- AUTHOR(S):
Oleksandr Salenko, Olga Chencheva, Viktor Schetinyn, Mohamed R.F.Budar, Valentina Gluchova
- ABSTRACT:
The paper presents an original solution to the actual problem of increasing the efficiency of the
drilling of composite materials of the carbonic group through the use of coupled electric rotary type
machines whose combination of movements allows to obtain controlled rotary-reciprocating motion
of the instrument. By creating cyclic low frequency load of the cutting zone, it is possible to improve
the efficiency and quality of processing, without destroying the composite.
- PAGES:
27-
- DOWNLOAD:
NEW DESIGN OF COMBINED ELECTRIC MACHINES TO INCREASE THE EFFICIENCY OF PROCESSING COMPOSITE MATERIALS
- TITLE:
DESIGN VARIANTS MODELING OF THE SMALL-SIZED GANTRY-TYPE MILLING MACHINE
- AUTHOR(S):
Yuriy Kuznietsov, Iurii Gaidaienko, Yuriy Krivchuk
- ABSTRACT:
Desktop CNC machines are designed for small-scale details manufacturing and form the
perspective direction of specialists training at design, research, development and operation of
machine-tool equipment of new generation. The research objective is to construct genetic models and
programs for directed synthesis of desktop milling machines without mechanical transmissions.
Evolution theory bases of electromechanical energy converters and genetic synthesis method of the
complex combined electromechanical structures, based on the genetic operators are used here. The
analysis of various approaches to kinematics of forming movements, to kinematic chains record and
modeling, and configurations of traditional performance machines and mechanisms of parallel
structure is made. New approach of genetic modeling on the example of the gantry-type milling
machine with linear electric motors is offered. There are first-ever created the genetic synthesis
models of small-sized milling machines without mechanical transmissions and discovered their
genetic programs, on which basis the original samples of desktop milling machines that can be used
successfully in production and educational process, are synthesized. This study is original in use of
innovative genetic approach to solving the tasks of desktop milling machines synthesis. The offered
approach can be used for synthesis of machines, robots and robotic systems of different function.
- PAGES:
20-
- DOWNLOAD:
DESIGN VARIANTS MODELING OF THE SMALL-SIZED GANTRY-TYPE MILLING MACHINE
- TITLE:
ELECTRON BEAM ADDITIVE MANUFACTURING OF LIGHT METALS
- AUTHOR(S):
Stefan Valkov, Peter Petrov
- ABSTRACT:
This article aims to summarize the topics related to the application of a surface manufacturing of
light metals by means of electron beam additive technologies for developing of new multifunctional
materials, as well as to modify their surface properties. These techniques have a large number of
applications in the field of automotive and aircraft industries for manufacturing of railways, space
crafts, different tools, and components. Some examples of the use of electron beams for surface
manufacturing and modification of structure and properties of Ti and Al based materials are
presented.
- PAGES:
17-
- DOWNLOAD:
ELECTRON BEAM ADDITIVE MANUFACTURING OF LIGHT METALS
