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Wyszukujesz frazę "Kodura, A." wg kryterium: Autor


Wyświetlanie 1-2 z 2
Tytuł:
An analysis of the impact of valve closure time on the course of water hammer
Autorzy:
Kodura, A.
Powiązania:
https://bibliotekanauki.pl/articles/240994.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
time of valve closure
butterfly valve
pressure characteristic
transient flow
water hammer
Opis:
The knowledge of transient flow in pressure pipelines is very important for the designing and describing of pressure networks. The water hammer is the most common example of transient flow in pressure pipelines. During this phenomenon, the transformation of kinetic energy into pressure energy causes significant changes in pressure, which can lead to serious problems in the management of pressure networks. The phenomenon is very complex, and a large number of different factors influence its course. In the case of a water hammer caused by valve closing, the characteristic of gate closure is one of the most important factors. However, this factor is rarely investigated. In this paper, the results of physical experiments with water hammer in steel and PE pipelines are described and analyzed. For each water hammer, characteristics of pressure change and valve closing were recorded. The measurements were compared with the results of calculations perfomed by common methods used by engineers – Michaud’s equation and Wood and Jones’s method. The comparison revealed very significant differences between the results of calculations and the results of experiments. In addition, it was shown that, the characteristic of butterfly valve closure has a significant influence on water hammer, which should be taken into account in analyzing this phenomenon. Comparison of the results of experiments with the results of calculations? may lead to new, improved calculation methods and to new methods to describe transient flow.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2016, 63, 1; 35-45
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Local cavitation due to water hammer
Autorzy:
Mitosek, M.
Kodura, A.
Rybak-Wilusz, E.
Powiązania:
https://bibliotekanauki.pl/articles/241414.pdf
Data publikacji:
2003
Wydawca:
Polska Akademia Nauk. Instytut Budownictwa Wodnego PAN
Tematy:
water hammer
cavitation
pressure oscillations
gas desorption
Opis:
The phenomenon of vapour cavitation due to water hammer is investigated ex-perimentally using high frequency pressure transducers (piezoelectric and strain gauges). The water hammer is caused by a sudden closure of a ball valve mounted at the end of the steel pipe. A short-duration pressure pulse, as well as high frequency cavitation pressure oscillations is observed. The high frequency pressure oscillations appear just after the vapour cavity collapse, whereas the pressure pulse does not occur immediately after collapse but is delayed from 0 to the water hammer period $2L/c$, s. The experiments have shown that the maxi-mum high frequency pressure oscillation, directly proportional to the pressure wave velocity, can be many times higher than the maximum water hammer pres-sure amplitude as well as short-duration pressure pulse. The influence of liquid evaporation duration and the steady state losses on the maximum high frequency cavitation pressure oscillation are shown. Growing pressure reduction is accom-panied by gas desorption from the liquid. The liberated air reduces the amplitude of the pressure increase and prolongs the period of oscillations. The experiments have shown that there are three phases of the maximum amplitude of high fre-quency pressure oscillations for each fixed steady state loss. The frequency of va-pour cavitation pressure oscillations depends on the duration of the oscillations. For the test cases, the frequency increases during the cavitation from ca. 400 to 900 Hz for steel pipes.
Źródło:
Archives of Hydro-Engineering and Environmental Mechanics; 2003, 50, 1; 59-72
1231-3726
Pojawia się w:
Archives of Hydro-Engineering and Environmental Mechanics
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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