Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

Wyszukujesz frazę "propagation velocity" wg kryterium: Temat


Wyświetlanie 1-3 z 3
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
Tytuł:
Influence of the crack propagation velocity on heat release in compressor blades during fatigue tests
Autorzy:
Bednarz, A.
Kuźniar, M.
Powiązania:
https://bibliotekanauki.pl/articles/244568.pdf
Data publikacji:
2016
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
crack propagation velocity
notch
thermovision
turbine engine
heat distribution
Opis:
In this work, the influence of the crack propagation velocity on heat release in blade was shown. Research was be performed during fatigue test of the compressor blade. In the investigations, the blade with the V-notch was examined. The blades during experiment were entered into transverse vibration by a vibration system Unholtz-Dickie UDCO-TA-250. The crack propagation process was conducted in resonance condition. The blades were periodically bended what simulates geometry changes during operation of the engine. The main part of the work is based on research of fatigue. During investigations both the amplitude of the crack length and also the blade tip displacement were controlled. Additional velocity of crack propagation was measured by change of a crack length in time. In the same time temperature, distribution pictures were observed. The taken picture was used to exhibit the phenomenon and shown the heat propagation direction. The main results of presented investigation are both the parameters of a crack and the crack growth dynamics in the compressor blade subjected to vibrations. An additional original result of the work is connection between velocity of crack propagation and temperature distribution taken from picture. The result of above analysis can be used in determining the amount of energy released during the cracking process and evaluate the amount of energy required for the growth of a gap. In this work, the capabilities of the proposed method and the problems associated with it were defined. The results presented in this paper have theoretical and practical value.
Źródło:
Journal of KONES; 2016, 23, 1; 67-73
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

    Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies