High-energy Nd-yag laser ignition of coals: Modeling analysis

Phuoc, Tran X.; Mathur, M. P.; Ekmann, J.M.; Durbetaki, P.

doi:10.1016/0010-2180(93)90119-n

Cited by 21 publications

(8 citation statements)

References 12 publications

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“…The area of the laser spot on the sample was S = 0.03 cm 2 . Sample glow was collected with lens (8) and recorded with the help of a photoelectron multiplier Hamamatsu H10721-20 (9) and oscillograph LeCroy WaveJet WJ332A (10). The time of laser radiation exposure was governed with the help of pulse generator G5-56 (11).…”

Section: Samples and Experimental Proceduresmentioning

confidence: 99%

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Ignition of Low-Metamorphized Coal with Continuous Lasers at Wavelengths 450 nm and 808 nm

Aduev

Belokurov

Liskov

et al. 2022

Eurasian Chem. Tech. J.

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The paper presents the results of a comparative investigation into the kinetic and energy characteristics of the ignition of microparticles of low-metamorphized coal ranks (lignite coal and high volatile C bituminous coal) under the impact of laser radiation at the wavelengths λ = 450 nm and λ = 808 nm with an exposure time of 1 sec. Coal ignition is carried out only during irradiation. There is no transition to stationary combustion. The ignition delay time decreases monotonically with increasing radiation power density. It is established that the energy costs of ignition of the studied coal ranks may be made more economical by using laser radiation with a wavelength of λ = 450 nm. It is concluded from the results of measuring the energy characteristics of coal ignition that the absorption of radiation has a quantum nature. Two components contribute to the coal particles emission spectra measured at the initial stage of ignition: CO (CO2*) flame and thermal glow associated with emitted carbon particles heated to T>2000 K for both coal ranks. At subsequent stages, only the glow of heated carbon particles with the thermal spectrum at T~2000 K is observed in the spectra.

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Section: Samples and Experimental Proceduresmentioning

confidence: 99%

“…Pulverized coal ignition with laser radiation is a very promising method. At present, works aimed at the studies of kinetic and energy characteristics of pulverized coal ignition with the help of pulsed neodymium and continuous CO 2 -lasers are carried out [4][5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Ignition of Low-Metamorphized Coal with Continuous Lasers at Wavelengths 450 nm and 808 nm

Aduev

Belokurov

Liskov

et al. 2022

Eurasian Chem. Tech. J.

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show abstract

“…The power meter, fitted with a 1 cm diameter mask, measured laser power incident on the pellet surface before each experiment. 5,15,20,[24][25][26][27] The predicted critical irradiance, I * , is presented in Fig. Table I with previously published experimental HMX laser ignition data.…”

Section: Laser Ignition Setupmentioning

confidence: 99%

Importance of the gas phase role to the prediction of energetic material behavior: An experimental study

Ali

Son

Asay

et al. 2005

Journal of Applied Physics

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Various thermal ͑radiative, conductive, and convective͒ initiation experiments are performed to demonstrate the importance of the gas phase role in combustion modeling of energetic materials ͑EM͒. A previously published condensed phase model that includes a predicted critical irradiance above which ignition is not possible is compared to experimental laser ignition results for octahydro-1,3,5,7-tetranitro-1,3,5,7-tetrazocine ͑HMX͒ and 2,4,6-trinitrotoluene ͑TNT͒. Experimental results conflict with the predicted critical irradiance concept. The failure of the model is believed to result from a misconception about the role of the gas phase in the ignition process of energetic materials. The model assumes that ignition occurs at the surface and that evolution of gases inhibits ignition. High speed video of laser ignition, oven cook-off and hot wire ignition experiments captures the ignition of HMX and TNT in the gas phase. A laser ignition gap test is performed to further evaluate the effect of gas phase laser absorption and gas phase disruption on the ignition process. Results indicate that gas phase absorption of the laser energy is probably not the primary factor governing the gas phase ignition observations. It is discovered that a critical gap between an HMX pellet and a salt window of 6 mm± 0.4 mm exists below which ignition by CO 2 laser is not possible at the tested irradiances of 29 W / cm 2 and 38 W / cm 2 for HMX ignition. These observations demonstrate that a significant disruption of the gas phase, in certain scenarios, will inhibit ignition, independent of any condensed phase processes. These results underscore the importance of gas phase processes and illustrate that conditions can exist where simple condensed phase models are inadequate to accurately predict the behavior of energetic materials.

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“…В [1] экспериментально подтверждено наличие двух механизмов лазерного зажигания образцов углей, как и предполагалось в [10]. В работе [5] отмечается, что механизм зажигания угля определяется его положением в генетическом ряду.…”

Section: Introductionunclassified

Спектральные Характеристики Свечения Пламен Каменных Углей Во Время Воздействия Лазерных Импульсов

Aduev¹,

Нурмухаметов²,

Крафт³

et al. 2022

Оптика И Спектроскопия

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The results of measuring the characteristics of the glow of coal flames at the initial moments of ignition under the action of laser pulses of a neodymium laser (1064 nm, 120 µs) are presented. In microparticles of coal grades DG, G, Zh, and K, when the corresponding critical energy densities are exceeded during a laser pulse, the surface ignites and flame propagates at a speed of V ≈ 50 m/s. The emission spectra of flames are contributed by the emission of emitted hot coal particles, excited H∗2 and H2O∗ molecules, as well as the flame emission arising from the oxidation of carbon (CO∗) and carbon monoxide (CO∗2) by atmospheric oxygen

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High-energy Nd-yag laser ignition of coals: Modeling analysis

Cited by 21 publications

References 12 publications

Ignition of Low-Metamorphized Coal with Continuous Lasers at Wavelengths 450 nm and 808 nm

Ignition of Low-Metamorphized Coal with Continuous Lasers at Wavelengths 450 nm and 808 nm

Importance of the gas phase role to the prediction of energetic material behavior: An experimental study

Спектральные Характеристики Свечения Пламен Каменных Углей Во Время Воздействия Лазерных Импульсов

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