Coefficient of mutual overlap in metal-polymer tribosystems

Abstract The polymer hybrid material under study is used as an antifriction coating of the friction contact surface. The experimental studies have been carried out on a special test bed with a reciprocating motion of the tribosystem in conditions of a mutual overlap coefficient less than one. The influence of the most important operational parameters, such as temperature, operating wear and wear rate, has been studied. The temperature was determined in the area of fixing the coating on a metal substrate, since the adhesive strength of the coating ensures the operability of this tribosystem. In addition, for the maximum friction modes, such standard parameters as the wear intensity and service life have been calculated. The wear resistance class has been set.

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Development and Research of Crosshead-Free Piston Hybrid Power Machine

Machines ◽

10.3390/machines9020032 ◽

2021 ◽

Vol 9 (2) ◽

pp. 32

Author(s):

Viktor Shcherba ◽

Viktor Shalay ◽

Evgeniy Nosov ◽

Evgeniy Pavlyuchenko ◽

Ablai-Khan Tegzhanov

Keyword(s):

Experimental Studies ◽

Operational Parameters ◽

Work Processes ◽

Free Piston ◽

Hybrid Power ◽

Power Machine ◽

Hybrid Power Machine ◽

Simplifying Assumptions ◽

Cylinder Piston ◽

Groove Seal

This article considers the development and research of a new design of crosshead-free piston hybrid power machine. After verification of a system of simplifying assumptions based on the fundamental laws of energy, mass, and motion conservation, as well as using the equation of state, mathematical models of the work processes of the compressor section, pump section, and liquid flow in a groove seal have been developed. In accordance with the patent for the invention, a prototype of a crosshead-free piston hybrid power machine (PHPM) was developed; it was equipped with the necessary measuring equipment and a stand for studying the prototype. Using the developed mathematical model, the physical picture of the ongoing work processes in the compressor and pump sections is considered, taking into account their interaction through a groove seal. Using the developed plan, a set of experimental studies was carried out with the main operational parameters of the crosshead-free PHPM: operating processes, temperature of the cylinder–piston group and integral parameters (supply coefficient of the compressor section, volumetric efficiency of the pump section, etc.). As a result of numerical and experimental studies, it was determined that this PHPM design has better cooling of the compressor section (decrease in temperature of the valve plate is from 10 to 15 K; decrease in temperature of intake air is from 6 to 8 K, as well as there is increase in compressor and pump section efficiency up to 5%).

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Numerical Modeling and Experimental Studies of the Operational Parameters of the Earth-To-Air Heat Exchanger of the Geothermal Ventilation System

Rocznik Ochrona Środowiska ◽

10.54740/ros.2021.003 ◽

2021 ◽

Vol 23 ◽

pp. 42-64

Author(s):

Boris Basok ◽

Ihor Bozhko ◽

Maryna Novitska ◽

Aleksandr Nedbailo ◽

Myroslav Tkachenko

Keyword(s):

Heat Exchanger ◽

Heat Exchangers ◽

Ventilation System ◽

Experimental Studies ◽

Operating Conditions ◽

Operational Parameters ◽

Cross Sectional ◽

Distinctive Features ◽

Sectional Shape ◽

Experimental Bench

This article is devoted to the analysis of the heat engineering characteristics of the operation of an Earth-to-Air Heat Exchanger, EAHE, with a circular cross-sectional shape, which is a component of the geothermal ventilation system. The authors analyzed literature sources devoted to the research of heat exchangers of the soil-air type of various designs and for working conditions in various soils. Much attention is paid to the issues of modeling the operation of such heat exchangers and the distinctive features of each of these models. Also important are the results of experimental studies carried out on our own experimental bench and with the help of which the numerical model was validated. The results of these studies are the basis for the development of a method for determining the optimal diameter of an EAHE under operating conditions for soil in Kyiv, Ukraine.

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Determination of the time of ignition of plant raw under the high temperature of the radiation panel

Ukrainian Journal of Forest and Wood Science ◽

10.31548/forest2020.03.008 ◽

2020 ◽

Vol 11 (3) ◽

Author(s):

V. V. Lomaha ◽

O. Yu. Tsapko ◽

Yu. V. Tsapko ◽

O. P. Bondarenko

Keyword(s):

High Temperature ◽

Fire Protection ◽

Effective Means ◽

Experimental Studies ◽

Fire Retardant ◽

Protective Layer ◽

Thermal Action ◽

Environmental Safety ◽

Wood Products ◽

Operational Parameters

Reducing the fire prevention of timber is not only an economic task, but also has a social and environmental focus. From economic, technological and environmental perspective, an important problem in ensuring the viability and safe operation of construction sites is the development of fire-retardant coatings for wooden structures. The construction is increasingly looking for new highly effective means of fire protection of wood and wood products which should not only ensure the standardized fire resistance of wood, but also to maintain its operational parameters to solve environmental safety and durability. Studies of the effect of the radiation panel on the ignition of the wood sample have set the parameters of the flame ignition, which makes it possible to influence this process. It is proved that they consist in the formation of a layer of organic material on the surface, which provides heating to a critical temperature, when the intensive decomposition of the material begins with the release of the required amount of combustible gases and their ignition. This makes it possible to determine the effect of fire protection and the properties of protective compositions on the process of slowing down the rate of burning of wood. Experimental studies have confirmed that the untreated sample of wood, under the thermal action of the radiation panel has taken up, the flames spread over the entire surface, which led to its combustion. The application of a fire retardant varnish under the influence of temperature leads to a layer of foam coke and inhibition of heat transfer of high-temperature flame to the material and its ignition. Thanks to this, it became possible to determine the conditions for changing the parameters of combustion and braking during fire protection of wood, by forming a barrier for thermal conductivity. Thus, there is reason to argue for the possibility of directional control of the processes of fire protection of wood by the use of fireproof coatings that can form a protective layer on the surface of the material, which slows down the rate of burning of wood.

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Experimental studies on particle emissions from cruising ship, their characteristic properties, transformation and atmospheric lifetime in the marine boundary layer

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-7-15105-2007 ◽

2007 ◽

Vol 7 (5) ◽

pp. 15105-15154 ◽

Cited By ~ 3

Author(s):

A. Petzold ◽

J. Hasselbach ◽

P. Lauer ◽

R. Baumann ◽

K. Franke ◽

...

Keyword(s):

Boundary Layer ◽

Particle Number ◽

Marine Boundary Layer ◽

Experimental Studies ◽

Test Bed ◽

Test Rig ◽

Particle Emissions ◽

Airborne Measurements ◽

Emission Studies ◽

Transformation Processes

Abstract. Particle emissions from ship engines and their atmospheric transformation in the marine boundary layer (MBL) were investigated in engine test bed studies and in airborne measurements of expanding ship plumes. During the test rig studies, detailed aerosol microphysical and chemical properties were measured in the exhaust gas of a serial MAN B{&}W seven-cylinder four-stroke marine diesel engine under various load conditions. The emission studies were complemented by airborne aerosol transformation studies in the plume of a large container ship in the English Channel using the DLR aircraft Falcon 20 E-5. Observations from emission studies and plume studies combined with a Gaussian plume dispersion model yield a consistent picture of particle transformation processes from emission to atmospheric processing during plume expansion. Particulate matter emission indices obtained from plume measurements are 8.8±1.0×1015(kg fuel)−1 by number for non-volatile particles and 174±43 mg (kg fuel)−1 by mass for Black Carbon (BC). Values determined for test rig conditions between 85 and 110% engine load are of similar magnitude. For the total particle number including volatile compounds no emission index can be derived since the volatile aerosol fraction is subject to rapid transformation processes in the plume. Ship exhaust particles occur in the size range Dp<0.3 μm, showing a bi-modal structure. The combustion particle mode is centred at modal diameters of 0.05 μm for raw emissions to 0.10 μm at a plume age of 1 h. The smaller-sized volatile particle mode is centred at Dp≤0.02 μm. From the decay of ship exhaust particle number concentrations in an expanding plume, a maximum plume life time of approx. 24 h is estimated for a well-mixed marine boundary layer.

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