Wyniki wyszukiwania - BazTech

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Zależność rozdziału wody od współczynnika przepływu dla wybranych tryskaczy ESFR

Domżał A., Wnęk W., Prokop M.

Bezpieczeństwo i Technika Pożarnicza

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2016

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Vol. 43, nr 3

63--72

PL

Cel: Celem artykułu jest przedstawienie wyników badań laboratoryjnych dla wybranych tryskaczy szybkiego reagowania o średnicy 20 mm tzw. ESFR (Early Supression Fast Response). Tryskacze były poddane badaniu na rozkład wody poniżej i powyżej deflektora w celu ustalenia proporcji rozkładu wody nad przestrzenią planowaną do zabezpieczenia przez instalację tryskaczową. Opisano metodykę badawczą, podano zmierzone parametry wpływające na wyniki badań oraz wskazano przykłady zastosowania badanych tryskaczy w warunkach rzeczywistych. Wprowadzenie: Pożary stanowią duże zagrożenie dla zdrowia i życia ludzi. W związku z tym poszukiwane są rozwiązania w zakresie elementów liniowych instalacji tryskaczowych, które umożliwią podawanie jak największej ilości wody na palącą się substancję. Elementem wpływającym na efektywność gaszenia jest równomierność zraszania oraz rozdział wody. Innymi słowy, ile wody podawane jest na powierzchnię pod tryskaczem, a ile na strop budynku. Metodologia: Artykuł został opracowany na podstawie wyników badań laboratoryjnych przeprowadzonych według normy PN-EN 12259-1. Stałe urządzenia gaśnicze. Podzespoły urządzeń tryskaczowych i zraszaczowych. Część 1: Tryskacze. Wnioski: Instalacje tryskaczowe umożliwiają zwalczenie pożaru w pierwszej fazie jego wystąpienia oraz zapobiegają jego rozprzestrzenianiu się. Ich główną zaletą jest selektywne działanie, pozwalające na ograniczenie akcji gaśniczej tylko do miejsca wystąpienia pożaru, a więc zredukowanie strat spowodowanych działaniem wody. Z przeprowadzonych pomiarów wynika, że: – tryskacze ESFR jako elementy liniowe instalacji tryskaczowej zraszają powierzchnię z dużą intensywnością zależną od ciśnienia, sięgającą dla badanych elementów powyżej 460 l/min, – duże intensywności zraszania generują potrzebę postawienia szczególnych wymagań co do rozmieszczania i doboru rodzaju instalacji tryskaczowej, – na rozdział rozpraszanej wody poniżej, jak i powyżej deflektora ma wpływ współczynnik przelotowości K badanych tryskaczy, – przy wzroście współczynnika K wzrasta rozdział wody, co powoduje zmianę w postaci wzrostu ilości wody poniżej deflektora dla badanego tryskacza wiszącego, – przy wzroście współczynnika K w funkcji ciśnienia osiągane są większe zmiany wydajności wodnej tryskaczy poniżej, jak i powyżej deflektora.

EN

Aim: The purpose of this paper is to present the results from experiments involving the distribution of water from selected quick-response sprinklers with a diameter of 20 mm, known as Early-Suppression Fast-Response (ESFR) sprinklers. Introduction: Fires are the cause of great risks to human life and health. There is a search for solutions to address the linear elements of sprinkler systems which facilitate the delivery of the maximum volume of water onto materials exposed to a fire. The elements which influence extinguishing effectiveness include the uniformity of spray and the dispersion of water. In other words, the volume of water delivered to the surface area beneath the sprinkler and to the roof of a building. Methodology: The paper was based on research results derived from studies conducted in accordance with PN-EN 12259-1, dealing with fixed extinguishing systems - elements of sprinkler systems, Part 1, Sprinklers. Sprinklers were tested for water distribution above and below the deflector to establish the proportion of water distributed above the protected area. The testing methodology was appropriately described and the parameters which influenced the results were identified. Additionally, the use of tested sprinklers was exemplified in real-life conditions. Conclusions: Sprinkler systems facilitate the successful extinguishing of fires during the initial phase of fire development and also prevent the propagation of flames. The main advantage of sprinkler systems is their selective operation. By concentrating extinguishing activities on the immediate area of a fire, potential damage caused by water activity are reduced. The experimental results demonstrate that depending on pressure, ESFR sprinklers used as linear elements in a sprinkler installation can spray an area with considerable intensity. For the tested elements, achieved levels were in excess of 460 l/min, – a high spray intensity can mean different requirements for the location and application of sprinklers, – water distribution above and below the deflector can be influenced by the K-factor of tested sprinklers, – increasing the K-factor intensified the distribution of water, which in turn increased the amount of water below the deflector of a suspended test sprinkler, – by increasing the K-factor as a function of pressure, greater changes are achieved in the water output of sprinklers above and below the deflector.

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Wpływ zastosowania deflektora w skrzynce rozprężnej na charakterystykę strumienia powietrza dostarczanego przez nawiewnik perforowany

Ogłodziński K., Chludzińska M., Bogdan A.

Ciepłownictwo, Ogrzewnictwo, Wentylacja

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2014

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T. 45, nr 10

394--396

PL

W artykule przedstawiono wyniki badań, których celem było określenie wpływu zastosowania wkładki deflekacyjnej na charakterystykę nawiewanego strumienia. Deflektor zlokalizowany został w skrzynce rozprężnej nawiewnika niskich prędkości o perforowanej płycie czołowej. Badania wykonano w dwóch wariantach - z zastosowaniem deflektora i bez jego użycia. Badania przeprowadzono przy dwóch różnych stopniach perforacji płyty czołowej, w warunkach izotermicznych, przy utrzymaniu stałego wydatku strumienia powietrza nawiewanego na poziomie 36 m3/h.

EN

The article presents the results of a pilot studies which aim was to demonstrate the effect of the application of deflector on the characteristics of the supply airflow. The deflector was located in the low-speed-diffuser's plenum box. A study was performed in two variants - with and without deflector use. The research was conducted for two different degrees of perforation of a front panel, in isothermal conditions while maintaining a constant supply air flow at 36 m3/h.

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Evaluation of impact of the deflector shape on effectiveness of weakening the blast wave originating from a mine or IED

Panowicz R., Nowak J., Konarzewski M.

Journal of KONES

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2013

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Vol. 20, No. 2

329--334

EN

The situations which our forces faced during various stabilization military missions showed that light armored vehicles are not secure enough in the case of the mine or improvised explosive devices explosion. Nowadays, the primary way of protection against this type of threat is application of a V-shape bottom in the vehicle. Such a configuration of the bottom allows dissipation of explosion energy whereby the impulse, which is transmitted to the construction – the vehicle bottom or frame, has a much lower value than in the case where the bottom is flat. In the literature it is possible to find the results of model tests on an experimental laboratory test stand. These studies show that the value of the impulse which is transmitted to the structure depends on the shape of the deflector, actually on its angle. Assuming the above condition, there were performed numerical analyses of the values of the impulse transmitted to the construction for deflectors with different angles and for a variety of loads masses. The aim of the numerical analyses was to find the optimal angle of the deflector for the considered situation. In this model, the optimal value of the angle is that in which the considered value of the impulse transmitted to the construction reaches the minimum value. For this purpose, there was made a finite element model of deflector corresponding to the conditions of the experiment. The shell elements were used in this model. The model was loaded with a pressure impulse derived from the detonation of an explosive. The blast wave interaction with the structure was modeled using the fluid structure interaction. The numerical analyses were based on the finite element method with the explicit time integration method implemented in the LS-DYNA program.

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Experimental investigation of deflector's angle influence on energy absorption

Gieleta R., Barnat W., Niezgoda T.

Journal of KONES

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2012

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Vol. 19, No. 4

201-205

EN

Numerical simulations without preliminary validation and model verification are vulnerable to errors. Best results are obtained when full experimental research is provided. Such tests are expensive and may be dangerous. Due to cost control and personnel safety, studies are often done in scale. Scale can affect both construction dimensions and applied load. In this paper four different vehicle's bottoms are examined: flat bottom and 3 types of deflectors. The paper presents four different vehicle's bottom shapes in order to examine deflector angle influence on energy absorption. The test included 4 cases: flat bottom broken-shaped deflector and deflectors with different apex angles 124 centigrade and 144 centigrade. For all cases the distance between explosive and panel was approximately 400 mm. The charge used was 100 g TNT. Flat bottom and deflectors were made of St3 steel with 2 mm thickness. For the purpose of the research a special test stand to examine effects of detonation wave was used. The force measurement system was designed in Department of Mechanics and Applied Computer Science. As a result, force versus time plots were obtained. The use of any deflector decreases maximum force affecting vehicle's hull.

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Influence of armoured vehicle's bottom shape on the pressure impulse

Barnat W., Panowicz R., Niezgoda T.

Journal of KONES

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2011

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Vol. 18, No. 1

39-46

EN

This paper presents the results of a numerical analysis of military vehicles hulls mine resistance. The research concerns armours loaded with blast wave from large IED charges in three cases. First is an explosion in Euler domain without any boundary conditions. Second consists of Euler domain with flat bottom and the ground. Third is simulated Euler domain with ground and deflector. Boundary conditions used both in second and third case resulted in growth of the pressure impulse due to the reflection from a rigid obstacle. In the article different hull bottom shapes are compared. The gap between the bottom and the ground is fixed in all cases. Explosion in Euler domain without limitations is added as a reference. The blast wave caused by the detonation (simulated as a point detonation) propagated in cubic mesh with appropriate boundary conditions. Theoretical solution of spherical non-linearity is given in a form of Taylor equations. It was used to verify the numerical model. The research showed that the ground proximity affects the results of the simulation. The pressure impulse is amplified due to the wave reflection from both the bottom of the vehicle and the ground. As well as that, the study confirmed that the usage of the deflector considerably reduces the impact load to the structure.

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Modern applications of high frequency acoustooptics

Petrov V.

Optica Applicata

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2004

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Vol. 34, nr 4

597-606

EN

The milestone applications of high frequency acoustooptics are discussed. The acoustooptical (AO) components such as Bragg modulator (including standing and running wave modulators), deflectors, others on very high frequencies (up to 10 GHz) working in wide frequency range (up to 3 GHz) are considered. Some review of traditional and modern uses is given. The main principles and peculiarities of Bragg cells design are discussed. The results of experimental investigationappeart to correspond with theoretical predictions. The specific problems which are stipulated by a very high frequency range are considered. These are: great influence of sound attenuation; peculiarities of interaction geometry and light aperture formation; multilayer transducer features; electrical matching with electromagnetic power wave guide. The ways of optimizing the parameters of high frequency Bragg cells are discussed.

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A new extraction system for the upgraded AIC-144 cyclotron

Bakewicz E., Daniel K., Doruch H., Sulikowski J., Taraszkiewicz R., Morozov N., Samsonov E., Shakun N., Vorojtsov S.

Nukleonika

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2001

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Vol. 46, nr 2

51-57

EN

This paper is a description of the computer simulation and the first experimental results on an AIC-144 isochronous cyclotron new extraction system. The cyclotron will be able to generate beams of protons, deuterons and alfa particles. One of the principal goals of the upgraded facility is to extract beams of protons and deuterons (proton energy 60 MeV, deuteron energy 30 MeV) for proton radiotherapy and for fast neutron beams. The precession method for particle extraction was chosen as the best one. It is the first time that the proton beam of energy 35 MeV has been extracted from the AIC-144 cyclotron with an efficiency of above 50%. More careful adjustment of the extraction system parameters (better control of the 1st harmonic of the magnetic field and the position of the deflectors) will permit an increase in the extraction efficiency to the design value of 70%.