Wyniki wyszukiwania - BazTech

1

Tłumienie wybuchu metanu z wykorzystaniem wysokociśnieniowej gaśnicy

Szkudlarek Z., Klemens R., Gieras M.

Przegląd Górniczy

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2014

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T. 70, nr 4

74--80

PL

W artykule przedstawiono wstępne badania laboratoryjne nad skutecznością tłumienia wybuchów metanu z wykorzystaniem wysokociśnieniowej gaśnicy. Jako materiału tłumiącego użyto proszku gaśniczego składającego się głównie z kwaśnego węglanu sodu (NaHCO3). Badania prowadzone były w komorach wybuchowych o pojemnościach 1,3 m3 i 10 m3, w których badano wpływ parametrów decydujących o procesie rozpylania i określano skuteczność tłumienia wybuchu metanu oraz na poligonie doświadczalnym, gdzie badano kształt i zasięg obłoku proszku gaśniczego wysokociśnieniowej gaśnicy. Przeprowadzone badania laboratoryjne pozwoliły na wyeliminowanie niedoskonałości w konstrukcji gaśnicy o objętości 10 dm3 oraz wykazały, że możliwe jest skuteczne tłumienie w początkowej fazie wybuchu metanu.

EN

This paper presents the initial laboratory tests on efficiency of suppression of methane explosion with the use of the high- -pressure fire extinguisher. Extinguishing powder consisting mainly of sodium bicarbonate (NaHCO3) was used. The tests were carried out in explosion chambers of capacity 1.3 m3 and 10 m3, in which the parameters decisive in powder spraying were tested as well as efficiency of suppression of methane explosion was determined. In addition, the shape and range of powder cloud ejected from high-pressure extinguisher were tested in the experimental field. The tests enable w eliminate any imperfections in the design of fire extinguisher of capacity 10 dm3 and have proved that it is possible to extinguish successfully methane explosion at its early stage.

2

Effectiveness of an active dust and gas explosion suppression system

Gieras M., Klemens R.

Journal of Power Technologies

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2012

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Vol. 92, nr 1

1-11

EN

The research aimed to test the effectiveness of gas and dust explosion suppression by means of a super fast explosion suppression system with a volume of 5 dm3. Smokeless powder as an explosive charge and sodium bicarbonate as a suppressing material were used. The experiments were carried out using a prototype device - a 5 liter steel container, closed by means of an aluminum membrane. Approximately 1.75 kg of extinguishing powder was placed in the container. The membrane was ruptured by exploding a specially developed charge located inside a perforated steel combustion chamber and mounted over the suppressing powder surface. The system was triggered by a signal from the protected volume, sent by a pressure transducer or by a photodiode reacting to a developing flame. The investigations into the efficiency of the active explosion suppression system were carried out in the 1.3 m3 explosion chamber. The explosion was initiated in a corn starch-air mixture of 0.2 kg/m3 concentration, or in a methane-air mixture of 7.5% and 8.5% CH4 concentration. The explosion suppression process occurred through the action of the extinguishing powder blown out from the extinguisher after the compressed combustion products perforated the membrane.

3

Analiza dynamiczna komory do badania urządzeń górniczych w warunkach eksplozji

Klemens R., Zagrajek T., Kobiera A., Żydak P., Kozioł S., Zbrowski A.

Problemy Eksploatacji

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2009

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nr 3

97-106

PL

W artykule przedstawiono przebieg i wyniki analizy obciążeń działających na płaszcz komory ciśnieniowej przeznaczonej do badania urządzeń górniczych w atmosferach gazów palnych w warunkach wybuchu. Przeprowadzono analizę zależności maksymalnego ciśnienia wywołanego wybuchem od rodzaju mieszanin gazowych i charakteru ich spalania. Określono maksymalne naprężenia występujące w płaszczu komory podczas wybuchu i wymagania wytrzymałościowe materiału konstrukcyjnego przeznaczonego do jego budowy.

EN

The article presents the course and results of the analysis of loads influencing the shell of the pressure chamber meant for testing mining devices in the combustible gas atmospheres in the explosion conditions. The analysis of the dependence of maximum pressure caused by the explosion on the type of gaseous mixtures and the character of their combustion was carried out. The maximum stresses occurring in the chamber's shell during the explosion and resistance requirements of the engineering material meant for building the shell were determined.

4

Numerical simulation of dust lifting process from the layer behind propagating shock wave

Zydak P., Klemens R.

Journal of KONES

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2006

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Vol. 13, No. 2

465-477

EN

The numerical simulations of physical processes constitute a great challenge for scientists. Many new models have been being developed and the ones that already exist are being improved. Many experiments are no longer needed to be performed in reality but can be replaced by numerical simulations. Many others that could not be done up to now, due to high cost or technical unfeasibility, can be performed using numerical models. Despite that many problems have not been fully resolved lots of work is still to be done. One of the phenomena that has not been fully explained and properly modeled - is the dust listing process from the layer. In the current research, the model of dust lifting process has been developed where the dust is not modeled directly but replaced by an injection of dust from the bottom of the channel. The parameters of the dust injection were obtained from previous experiments. The main advantage of this approach is the possibility of using sparse meshes which are required in modeling of large scale geometries. The model was implemented in a CFD code and calculations were made to test the ability of the model to simulate dust dispersion from a layer in a shock tube. The results were compared with the experimental data and a good agreement was concluded

5

Modelowanie matematyczne wybuchów mieszanin pyłowo-gazowych

Klemens R., Kosiński P., Wolański P.

Prace Naukowe Politechniki Warszawskiej. Konferencje

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2002

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T. 2, z. 22

629-636

PL

Praca obejmuje problematykę modelowania wybuchów mieszanin pylowo-gazowych w kanałach. W oparciu o analizę badanych zjawisk wybrano i opracowano model, który według autorów nadaje się najlepiej do wykorzystania w symulacjach rzeczywistych wybuchów mieszanin pylowo-gazowych. Na podstawie opracowanego modelu matematycznego został stworzony program komputerowy, który ma za zadanie służyć zarówno jako narzędzie umożliwiające analizę wielu zjawisk, jak również symulowanie rzeczywistych eksperymentów.

EN

The paper is devoted to the problems of mathematical modelling of dust-air mixtures explosions. After analysis of the phenomena a model has been chosen that is the most suitable for simulations of real dust-air mixtures explosions. Basing on the model a computer code has been created, whose task is to perform numerical experiments of large-scale explosions.

6

Symulacja numeryczna procesu propagacji wybuchu mieszanin gazowych w kanałach w obecności przeszkód

Klemens R., Kosiński P.

Archiwum Spalania

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2002

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Vol. 2, nr 2

96-112

PL

W pracy przedstawiono zarys problematyki wybuchów mieszanin gazowych oraz specjalnie opracowany model matematyczny, służący do symulacji komputerowych tego typu zjawisk. Pokazano, jak za pomocą pakietu komputerowego można przeprowadzać obliczenia rzeczywistych wybuchów mieszanin gazowych oraz badać wpływ różnych parametrów na przebieg procesu. Zwrócono uwagę przede wszystkim na obecność obiektów stałych w kanałach i w instalacjach, gdzie może zaistnieć wybuch.

7

Mathematical modelling of dust layer dispersion due to rarefaction waves

Klemens R., Kosinski P., Oleszczak P.

Archivum Combustionis

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2002

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Vol. 22 nr 1-2

3-12

EN

One of the methods of dust explosions mitigation is the use of venting systems, the task of which is to diminish the pressure rise. Nevertheless, the systems posses some inherent drawbacks. One of them is the presence of rarefaction wave, which propagates back and may interact with dust layers, which are present inside the facility. The objective of the study is to simulate the process of dust lifting caused by rarefaction waves and show how it may lead to the formation of combustible dust-air cloud.

8

Numerical modelling of coal mine explosion

Klemens R., Kosinski P., Wolanski P., Korobeinikov V. P., Markov V. V., Menshov I. S., Semenov I. V.

Archivum Combustionis

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2001

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Vol. 21 nr 1

71-79

EN

The investigation of unsteady processes behind shock waves propagating in a gasdust combustible mixture is very important to understand mechanisms of industrial dust explosions like those in coal mines. In the paper, two aspects of this study are considered. The first one concerns questions related to ignition and burning of the mixture, where some results are given of numerical investigation of the transition to detonation process. Also 2D structure of unsteady detonation in the mixture of coal particles with air is taken into consideration. In the applied model, the moving medium is treated as a two-phase, two-velocity and two-temperature continuuum with mechanical and thermal interaction between the phases. Devolatilization, gas-gas and gas-particle exothermic chemical reactions, radiation and heat conduction are also taken into account. The other aspect is the problem of the dust enhancement and dispersion from the dust layer behind a shock wave. The forces caused by particles rotation and gas vorticity are taken additionally into account. Two numerical methods were developed to solve numerically the considered problems. Examples of calculations are presented.

9

Structure of dust - air flame

Klemens R., Gieras M., Szatan B.

Archivum Combustionis

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2000

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Vol. 20 nr 1-2

41-48

EN

In the presented work the dust-air flames structure was studied. The flame propagation process was visualized by using the Schlieren and interferometric methods. Frame, streak and compensation photography was used for study the flame structure. Temperature was measured by means of a resistance thermometer.