Minimum ignition energy and quenching distance of aluminum dust clouds

2021 ◽  
Author(s):  
Meet Parikh ◽  
Rinrin Saeki ◽  
Rajib Mondal ◽  
Kwangseok Choi ◽  
Wookyung Kim
Keyword(s):  
Ignition Energy ◽  
Minimum Ignition Energy ◽  
Dust Clouds ◽  
Quenching Distance

Ignition and flame quenching of quiescent dust clouds of solid fuels

1980 ◽  
Vol 369 (1739) ◽  
pp. 479-500 ◽  
Keyword(s):  
Mass Transfer ◽  
Particle Size ◽  
Dust Concentration ◽  
Solid Fuels ◽  
Ignition Energy ◽  
Minimum Ignition Energy ◽  
Transfer Number ◽  
Dust Clouds ◽  
Nitrogen Ratio ◽  
Quenching Distance

Experiments have been carried out to study the influence of particle size, dust concentration, pressure, mass transfer number and oxygen/nitrogen ratio on quenching distance and minimum ignition energy of dust clouds of solid fuels. The solids chosen were aluminium, magnesium, titanium and carbon. Ignition was accomplished by using sparks whose energy and duration could be varied independently. A separate series of tests was also conducted to ascertain optimum spark duration. The results of these tests show that particle size has a strong influence on the minimum ignition energy, the quenching distance and the optimum spark duration. To a lesser extent pressure, dust concentration, mass transfer number and oxygen/nitrogen ratio also affect ignition and quenching of dust clouds. A detailed comparison of results for the dust clouds and the liquid mists studied previously shows a strong similarity between the two. It appears that both solid and liquid fuels may be treated as members of a single family. Thus it is found that the formulae for quenching distance and minimum ignition energy derived previously for liquid fuel mists also satisfactorily predict the experimental results obtained for dust clouds of metals and carbon. Further, a typical calculation shows that for aluminium, for example, the critical particle Sauter mean diameter below which the formulae become invalid is around 6 μm.

Ignition and flame quenching of quiescent fuel mists

1978 ◽  
Vol 364 (1717) ◽  
pp. 277-294 ◽  
Keyword(s):  
Reaction Rates ◽  
Ignition Energy ◽  
Minimum Ignition Energy ◽  
Proposed Model ◽  
Theoretical Predictions ◽  
Quenching Distance ◽  
Experimental Values ◽  
Sole Criterion ◽  
Fuel Vapour ◽  
Level Of Agreement

A model is proposed for the ignition of quiescent multidroplet fuel mists which assumes that chemical reaction rates are infinitely fast, and that the sole criterion for successful ignition is the generation, by the spark, of an adequate concentration of fuel vapour in the ignition zone. From analysis of the relevant heat transfer and evaporation processes involved, ex­pressions are derived for the prediction of quenching distance and minimum ignition energy. Support for the model is demonstrated by a close level of agreement between theoretical predictions of minimum ignition energy and the corresponding experimental values obtained using a specially designed ignition apparatus in which ignition energies are measured for several different fuels, over wide ranges of pressure, mixture composition and mean drop size. The results show that both quenching distance and mini­mum ignition energy are strongly dependent on droplet size, and are also dependent, but to a lesser extent, on air density, equivalence ratio and fuel volatility. An expression is derived to indicate the range of drop sizes over which the proposed model is valid.

scholarly journals A model for the minimum ignition energy of dust clouds

2019 ◽  
Vol 121 ◽  
pp. 43-49 ◽  
Author(s):  
Sepideh Hosseinzadeh ◽  
Jan Berghmans ◽  
Jan Degreve ◽  
Filip Verplaetsen
Keyword(s):  
Ignition Energy ◽  
Minimum Ignition Energy ◽  
Dust Clouds

Ignition and flame quenching in flowing gaseous mixtures

1977 ◽  
Vol 357 (1689) ◽  
pp. 163-181 ◽  
Keyword(s):  
Combustible Mixture ◽  
Inert Gases ◽  
Ignition Energy ◽  
Minimum Ignition Energy ◽  
Turbulence Scale ◽  
Gaseous Mixtures ◽  
Wide Range ◽  
Theoretical Predictions ◽  
Quenching Distance ◽  
Velocity Turbulence

The influence of pressure, velocity, turbulence intensity, turbulence scale and mixture composition on minimum ignition energy and quenching distance in flowing gaseous mixtures is examined experimentally for methane and propane fuels. In some experiments, the nitrogen in the air is replaced by various inert gases such as carbon dioxide, helium or argon, while in others the nitrogen is either partly or totally replaced by oxygen. The tests are conducted at room temperature in a 9 cm square working section through which the combustible mixture is arranged to flow at various levels of pressure, turbulence and velocity. At each test condition, the spark energy required to ignite the flowing mixture is measured for several gap widths in order to establish the optimum gap width corresponding to minimum ignition energy. From analysis of the relevant combustion and heat transfer processes involved, expressions for the prediction of quenching distance in flowing mixtures are derived. Support for the model employed in this analysis is demonstrated by a close level of agreement between theoretical predictions of quenching distance and corresponding values calculated from the experimental data on minimum ignition energy obtained over a wide range of mixture compositions and flow conditions.

Further studies on the ignition and flame quenching of quiescent dust clouds

1983 ◽  
Vol 385 (1788) ◽  
pp. 1-19 ◽  
Keyword(s):  
Heat Loss ◽  
Chemical Reaction ◽  
Coal Dust ◽  
Minimum Ignition Energy ◽  
Radiation Heat ◽  
Diffusion Term ◽  
Radiation Heat Loss ◽  
Dust Clouds ◽  
Quenching Distance ◽  
New Formula

The ignition and quenching of dust clouds of carbon, graphite, coal, aluminium and magnesium have been investigated. New experimental data on quenching distance and minimum ignition energy of graphite and coal dust in air and in oxygen-nitrogen mixtures are reported. These results show the influence of particle size, volatile matter, dust concen­tration and oxygen enrichment on the ignition and quenching processes. To explain these and earlier experimental observations, a new formula for the quenching distance has been derived. This expression incorporates ‘chemical reaction’ and ‘radiation heat loss’ terms in addition to a ‘diffusion’ term, which is retained from its earlier version (Ballal 1980). The new formula shows a significantly better prediction of the old and the new experimental results. The importance of chemical reaction and radiation heat loss in the study of ignition and quenching of dust clouds is discussed. Also, a strong similarity between the ignition and quenching characteristics of dust clouds, fuel mists and gaseous fuel-air mixtures is elucidated.

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