Pulse-contact frictional interaction of microprotrusions of friction pairs of brake devices

Volchenko, N.A.; Volchenko, D.A.; Polyakov, P. A.; Красин, Петр Сергеевич; Fedotov, Evgeny; Evchenko, A.S.

doi:10.1088/1757-899x/560/1/012194

Cited by 6 publications

(3 citation statements)

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“…We assume that this is how the specularity parameter changes with a change in the oxidation state. These found effects allow us to conclude that the surface conductivity method for changing the nanofluid properties, which becomes an electrolyte [42,43], leads to an increase in its thermal conductivity coefficient.…”

Section: State Of the Art And Problem Statementmentioning

confidence: 76%

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Nanofluids in Cooling Systems and Their Efficiency

Volchenko¹,

Киндрачук²,

Dolishniy³

et al. 2021

J. Nano- Electron. Phys.

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In the materials of the article, it is shown that based on multifactor analysis, the proposed models of nanofluids are taken into account in the base fluids; a collision between nanoparticles and molecules; nanoparticles that occur due to Brownian motion; thermal diffusion of nanoparticles and their interaction with molecules; formation of percolation trajectories with low heat capacity in a fluid; influence of interphase and boundary layers in the separation of the solid and fluid phases; the surface shell effect; thin nanolayers; particle clustering. The study of nanofluids comes down to determining their thermal conductivity coefficient. It is established that the obtained values of thermal conductivity coefficients, which are 10 times higher than usual, do not fit into the classical calculation schemes used to determine the heat transfer coefficients. For cavities of nanofluid cooling systems, the thermal resistances of heat transfer and thermal conductivity are fictitious in magnitude. This is due to the fact that in the cooling cavities, the driving force is the potential jumps between the layers of the nanofluid. We selected the materials for creating nanoliquids that will be used in the new design of the braking system. It is formed by Al2O3 particles enveloped by polymeric material FK-24A. The diameter of nanoparticles was 15, 35 and 80 m. An increase in particle size and concentration results in an increase in the thermal conductivity of the liquid. In place of nanoliquid and metal components contact, the electrical potential and intensity of the electric field of nanoliquid change, that is also described here. When the temperature of the nanofluid rises above 100 °C it may become an electrolyte. The use of nanofluids in lubrication of drawworks braking system reduces the wear of friction couples by ~ 20 % and increases the braking moment by about 13 %.

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Section: State Of the Art And Problem Statementmentioning

confidence: 76%

“…Consequently, along the surface of the pulley rim, the thickness of the boundary layer δТ(х) ~ х 0.5 increases [43,44] In this case, the local value of the heat transfer coefficient (х) ~ х 0.5 decreases proportionally (Fig. 4).…”

Section: Interaction Of Nanoparticles In Fluid Cooling Systemsmentioning

confidence: 99%

Nanofluids in Cooling Systems and Their Efficiency

Volchenko¹,

Киндрачук²,

Dolishniy³

et al. 2021

J. Nano- Electron. Phys.

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“…It should be noted that other components also make changes to the above processes and effects. It has been established that two double electric layers are formed in the brake friction couples: the first is the surface of the microasperities tops of the disc friction belt (negatively charged) -a layer of water between the microasperities (negatively charged); the second is the surface of the microasperities tops of the friction pad (positively charged) -a layer of water between the microasperities (negatively charged) [15][16][17][18][19][20][21]. J. NANO-ELECTRON.…”

Section: Processes and Effects Arising From The Frictional Interactiomentioning

confidence: 99%

Electrothermomechanical Friction of Wet Elements of Automotive Disc-shoe Brakes

Volchenko¹,

Ukraine²,

Киндрачук³

et al. 2020

J. Nano- Electron. Phys.

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In the article, attention is paid to the factors affecting the limiting wetting angle of both polished and matte side surfaces of solid and self-ventilated discs of vehicles brake devices when they are moving on a wet roadbed. The following factors are considered: the material of the friction elements and its structure, the energy level of the surface layer, the topography of the friction surfaces and the geometric parameters of their microasperities, the presence of pores and grooves in them, capillary, centrifugal and inertial forces and moments, dynamic equilibrium between the energy level of the friction surface and a water film on it. In examining the microgeometry of the disc friction surface, its area, the ratio of the microasperities height to their pitch, the intensity of changes in their height and the degree of contamination were taken into account. It was found that the surface microgeometry affects the heat of desorption of the water film. The research of the above factors has shown that the driving force of the processes and effects in wet brake friction couples are potential gradients arising as a result of action of transverse and longitudinal electric double layers. The triboelectric water-effected phenomena were studied. The test results of self-ventilated disc-shoe brakes of MAN trucks (model TGA 26.420) with dry and wet friction couples tested with 20-fold cyclic braking are presented (speed drop 30 km/h per 1 min). The registered temperature at the interface was 320-340 °C. As a result of the road tests carried out on a truck with wet brake friction couples, regularities of the braking time, braking torque and braking distance depending on the dynamic coefficient of friction were established. The analysis of the obtained data was carried out. The results of studies of the negative effect of water penetration into disc-shoe interface are given.

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