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Wyszukujesz frazę "flame propagation velocity" wg kryterium: Temat


Wyświetlanie 1-2 z 2
Tytuł:
Numerical simulations of lean propane-air flames propagating in circular tubes under quenching conditions
Autorzy:
Gutkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/244052.pdf
Data publikacji:
2008
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
flame quenching
flame propagation velocity
simulation
Opis:
Flame extinction in internal combustion engines can be observed when a flame front enters a small gap between the cylinder and piston or above the piston rings. This phenomenon is caused by the interaction of the flame with the walls. Cooling of the reaction zone by the wall is the reason for the flame extinction. Simplifying the problem to the propagation of a premixed laminar flame in the narrow channels with isothermal wall allowed employing numerical methods to analyze this phenomenon. The aim of this work was to examine flame behavior during its propagation in the narrow circular tube. A numerical analysis of the freely propagating flame was conducted. In this study, the propagation and quenching of a laminar premixed propane/air flame in circular tube was investigated numerically. The flame chemistry is modeled by one-step overall reaction. The considerations are limited to flames propagating downwards in lean propane-air mixtures. Quenching diameter as a function of equivalence ratio was determined. One of the most important flame parameters - flame propagation velocity (under quenching conditions) was compared with adiabatic burning velocity and limit burning velocity predicted by Zeldovich. It was found satisfactory agreement between numerical calculations and theoretical considerations. Numerical results show also that there is a close dependence between preheat zone and dead space for flames propagating in a wider tube.
Źródło:
Journal of KONES; 2008, 15, 2; 117-123
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of number of step reactions on flame parameters under quenching conditions
Autorzy:
Gutkowski, A.
Powiązania:
https://bibliotekanauki.pl/articles/242109.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
flame propagation
quenching diameter
flame propagation velocity
numerical simulation
Opis:
Last decade, construction and using of microscale gas-turbines and internal combustion engines is collecting growing attention. However, the flame propagation limitations impede the development of micro and mesoscale combustion devices. Due to its small scale, increasing effect of flame-wall interaction causes a large heat loss and in consequence flame quenching. Both, fundamental experimental work and numerical simulations are conducted in order to overcome quenching issues. The most basic analysis concerns flame behaviour in small scale devices are premixed flame propagation in narrow tubes. There are two possibilities of flame-flow configurations: flame moving in a stationary mixture and a stationary flame in mowing mixture. These configurations have influence on flame shape, flame propagation velocity and quenching diameter. Most of numerical investigation assumes single-step reaction. It means that for flames propagating in propane-air mixtures C3H8 reacts directly with oxygen and leads to CO2 and H2O. This chemical kinetics mechanism omits existence of CO in reaction zone and in combustion products. Therefore it is interesting to use two-step reactions mechanism and compare the results with those obtained from single-step reaction model. The purpose of this analysis is to find influence of number of reaction steps on flame behaviour under quenching conditions for flames propagating in stationary lean propane-air mixtures. Quenching diameter, flame propagation velocity are determined and analyzed.
Źródło:
Journal of KONES; 2011, 18, 2; 153-159
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-2 z 2

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