scholarly journals Automation of physical experiments regarding explosions of air-methane mixtures

2020 ◽  
Vol 305 ◽  
pp. 00013
Author(s):  
Adrian Bogdan Şimon-Marinică ◽  
Zoltan Vass

In the following study, experimental results are obtained from an automated stand. With the help of this experimental stand, visualization techniques such as Schlieren and Shadowgraph can be applied, to study the flame front propagation of air and inflammable gas mixtures initiation. In parallel, an infrared sensor was used to control a push-pull solenoid to open the gas escape diaphragm of the stand. To obtain the explosive gas mixture at various concentrations (between the lower explosion limit and the upper explosion limit) an original programmable mixer was used, based on computational algorithms for accurate control of stepper motors which allow attainment of air and inflammable gas flows in order to achieve a homogeneous and continuous mixture at the desired concentration. The performed experiments allow for a better understanding of the flame front production and propagation, facilitating the knowledge and optimization of the operating times from the reduction mechanisms for reducing the effects of explosions of the flammable gas-air mixtures.

1999 ◽  
Vol 10 (1) ◽  
pp. 27-53 ◽  
Author(s):  
X. SUN ◽  
M. J. WARD

In the small diffusion limit ε→0, metastable dynamics is studied for the generalized Burgers problemformula hereHere u=u(x, t) and f(u) is smooth, convex, and satisfies f(0)=f′(0)=0. The choice f(u)=u2/2 has been shown previously to arise in connection with the physical problem of upward flame-front propagation in a vertical channel in a particular parameter regime. In this context, the shape y=y(x, t) of the flame-front interface satisfies u=−yx. For this problem, it is shown that the principal eigenvalue associated with the linearization around an equilibrium solution corresponding to a parabolic-shaped flame-front interface is exponentially small. This exponentially small eigenvalue then leads to a metastable behaviour for the time- dependent problem. This behaviour is studied quantitatively by deriving an asymptotic ordinary differential equation characterizing the slow motion of the tip location of a parabolic-shaped interface. Similar metastability results are obtained for more general f(u). These asymptotic results are shown to compare very favourably with full numerical computations.


Energies ◽  
2017 ◽  
Vol 10 (9) ◽  
pp. 1337 ◽  
Author(s):  
Santiago Martinez ◽  
Adrian Irimescu ◽  
Simona Merola ◽  
Pedro Lacava ◽  
Pedro Curto-Riso

2010 ◽  
Vol 157 (10) ◽  
pp. 1825-1832 ◽  
Author(s):  
F. Halter ◽  
T. Tahtouh ◽  
C. Mounaïm-Rousselle

2002 ◽  
Vol 12 (11) ◽  
pp. 2547-2555 ◽  
Author(s):  
VADIM N. KURDYUMOV ◽  
AMABLE LIÑÁN

The flashback or propagation of premixed flames against the flow of a reacting mixture, along the low velocity region near a cold wall, is investigated numerically. The analysis, carried out using the constant density approximation for an Arrhenius overall reaction, accounts for the effects of the Lewis number of the limiting reactant. Flame front propagation and flashback are only possible for values of the near wall velocity gradient below a critical value. The flame propagation becomes chaotic for small values of the Lewis number.


2014 ◽  
Vol 59 (1) ◽  
pp. 52-59 ◽  
Author(s):  
M. M. Alekseev ◽  
M. V. Alekseev ◽  
V. P. Samsonov ◽  
O. Yu. Semenov

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