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Wyszukujesz frazę "Dmytriv, Vasyl" wg kryterium: Autor


Wyświetlanie 1-3 z 3
Tytuł:
Model of forced turbulence for pulsing flow
Autorzy:
Dmytriv, Vasyl
Powiązania:
https://bibliotekanauki.pl/articles/329078.pdf
Data publikacji:
2020
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
forced turbulence
velocity of pulsating flow
dynamic length
pressure drop
Karman constant
turbulencje
prędkość
przepływ pulsacyjny
spadek ciśnienia
stała Karmana
Opis:
The article deals with fluid motion along an infinite hose. Taking into consideration the Stokes equation, the tangential friction stresses according to Newton and the Reynolds equation, the differential equation of the velocity change in radius is developed taking into account the pulsating component of the friction forces in the turbulent flow. Turbulence is defined as the impulse component of a flow, characterized by a pressure drop along a dynamic length of flow, a frequency response, and an oscillation amplitude of the pressure drop of pulse (which is given by the time equation of the oscillation). The velocity distribution along the radius of the hose in the time interval of one second was modelled for pressure drops in the range from 6000 to 18000 Pa and the amount of transported medium in the range from 1.667·10-5 to 6.667·10-5 m3 , which corresponded to the length of pulse plug. The dynamic viscosity of the medium (milk) of 1.79 · 10-3 Pa·s and its density of 10273 N·s2 /m4 were accounted at the simulation. The developed analytical dependence of the velocity of the forced turbulence of the pulsating flow allows to calculate the absolute value of the velocity at a given point of crosssection of the pipeline, and characterizes the physical process of flow of Newtonian fluids and gases in the pipeline.
Źródło:
Diagnostyka; 2020, 21, 1; 89-96
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Management of technological process optimisation
Autorzy:
Lypchuk, Vasyl
Dmytriv, Vasyl
Powiązania:
https://bibliotekanauki.pl/articles/1819010.pdf
Data publikacji:
2020
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
workload factor
process productivity
analytical model
duration of operations
amount of equipment
współczynnik obciążenia pracą
produktywność procesu
model analityczny
Opis:
The research aims to characterise the optimisation of a technological process depending on the main time parameters for production. The optimisation does not require to correct technical parameters of a system, but rather the organisational and managerial factors of the technological process. The workload is taken as an evaluation criterion, which factors in the probability distribution of time characteristics of computer process operations. Time characteristics that represent the performance of an operation influence the workloads of an operator and equipment, determining the productivity of the technological process. Analytical models were developed for the operational control of a production line efficiency considering the probability–statistical parameters pertaining to the performance of operations and technological equipment peculiarities. The article presents research results, which characterise the dependence of a production line efficiency on the type of equipment, and the duration of preparatory and final operations considering their probability. Under an optimal workload of the operator, the duration of the complete program changes linearly, regardless of the time required for the performance of operations by a computer without the involvement of the operator, and depending on the type of equipment. A managerial decision can be optimal under the condition that the factor of technological process efficiency (K_TP) tends to max. The developed method of analytical determination can be used to calculate the workload of both an operator and technological equipment. The calculations of the duration of a production line operation resulted in the methodology for the consideration of probability characteristics pertaining to the time distribution of the period required to perform operations, which influences the unequal efficiency of the production line. The probabilistic character of time distribution related to intervals of performed operations serves as a parameter in the management of technological process optimisation, which can be achieved using simulators of technological processes optimised in terms of their efficiency.
Źródło:
Engineering Management in Production and Services; 2020, 12, 3; 103--115
2543-6597
2543-912X
Pojawia się w:
Engineering Management in Production and Services
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Analytical dynamic model of coefficient of friction of air pipeline under pressure
Autorzy:
Dmytriv, Vasyl
Dmytriv, Ihor
Horodetskyy, Ivan
Dmytriv, Taras
Powiązania:
https://bibliotekanauki.pl/articles/328390.pdf
Data publikacji:
2019
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
coefficient of friction
Mach number
pressure
aspect ratio
Reynolds number
analytical model
vacuum
współczynnik tarcia
liczba Macha
ciśnienie
współczynnik kształtu
liczba Reynoldsa
model analityczny
próżnia
Opis:
To transport of the air in the pipeline, an analytical model is developed that takes into account the gas velocity, its kinematic and dynamic characteristics - density, viscosity depending on the pressure in a given space of the pipeline. The analytical model makes it possible to calculate the coefficient of friction of gas transportation in the pipeline at intervals of the absolute pressure from 220 to 2 kPa and M < 1 Mach numbers, depending on the diameter and length of the pipeline and physical and technological characteristics of the gas. The K1* aspect ratio is proposed, which characterizes in time the ratio of the dynamic force of movement of gas to the static pressure related to the diameter of the pipeline. The coefficient of air friction was modeled according to the vacuum pressure as a parameter of density and air flow. Air flow was taken from 1.917·10-3 m 3/s to 44.5·10-3 m 3/s respectively, diameters from 0.030 to 0.070 m and Mach number was M = 0.005-0.13. At the vacuum and excess pressures with increasing of Reynolds number and decreasing of Mach number the gas friction coefficient increased linearly. According to the simulation results as the pressure loss and the diameter of the pipeline are increased the friction coefficient increased as well. Analogically, at the vacuum metric pressure when the pressure loss and the diameter of the pipeline are increased the friction coefficient increased. At the pipeline internal diameters of 22, 30, 36 mm accordingly for pressure losses from 2 to 14 kPa the coefficient of air friction varies from 0.006 to 54.527 respectively.
Źródło:
Diagnostyka; 2019, 20, 4; 89-94
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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