Modelling of syngas/air laser-induced ignition with the state-to-state vibrational kinetics taken into consideration

A thermal non-equilibrium kinetic model for a syngas/air mixture taking into account the state-to-state vibrational kinetics of CO, N2, O2, H2, and OH molecules was developed. Physico-chemical processes occurring in the mixture when CO molecule are highly vibrationally excited by the absorption of resonant CO laser radiation were considered. It was shown that non-equilibrium vibrational excitation of CO molecules leads to the acceleration of chemical reactions and allows to initiate the combustion of the syngas/air mixture effectively. Due to the radiation absorption and vibrational-chemistry coupling strongly non-Boltzmann vibrational distributions of molecule are formed, which has a considerable influence on the syngas combustion kinetics. The results of the state-to-state model were compared with the predictions of simplified models that do not take into account vibrational nonequilibrium or disruption of local Boltzmann vibrational distributions.

syngas, laser-induced ignition, vibrational non-equilibrium, state-to-state model

Volume 22, issue 6, 2021 year

Описание лазерно-индуцированного воспламенения синтез-газа в воздухе с использованием уровневой модели колебательной неравновесности

Была построена термически неравновесная кинетическая модель для описания воспламенения смеси синтез-газ/воздух, учитывающая поуровневую колебательную кинетику молекул CO, N2, O2, H2 и OH. С использованием построенной модели были рассмотрены физико-химические процессы, протекающие при воздействии на синтез-газ излучения CO-лазера. Показано, что неравновесное возбуждение колебаний молекул CO резонансным лазерным излучением приводит к ускорению химических реакций и позволяет инициировать воспламенение смеси синтез-газ/воздух. При этом функции распределения молекул по колебательным уровням, формирующиеся в неравновесном газе, сильно отличаются от распределений Больцмана, что необходимо учитывать при определении скоростей химических реакций. Проведено сравнение результатов, полученных с использованием уровневой модели, с результатами расчётов, выполненных в термически равновесном приближении, а также с использованием модели, не учитывающей нарушение локальных распределений Больцмана в модах молекул.

синтез-газ, лазерно-индуцированное воспламенение, колебательная неравновес-ность, уровневая модель

Volume 22, issue 6, 2021 year

1. Starik, A.M., Titova, N.S., “Effects of thermal nonequilibrium in combustion,” 33rd Thermo-physics Conference, AIAA Paper 1999-3637 (1999).
2. Voelkel, S., Masselot, D., Varghese, P.L., Raman, V., “Analysis of hydrogen–air detonation waves with vibrational nonequilibrium,” AIP Conf. Proc., 2016, Vol. 1786, P. 070015 (9pp).
3. Shi, L., Shen, H., Zhang, P., Zhang, D., Wen, C., “Assessment of vibrational non-equilibrium effect on detonation cell size,” Combust. Sci. Technol., 2017, Vol. 189, Pp. 841–853.
4. Kadochnikov, I.N., Arsentiev, I.V., “Modelling of vibrational nonequilibrium effects on the H2–air mixture ignition under shock wave conditions in the state-to-state and mode approxima-tions,” Shock Waves, 2020, Vol. 30, Pp. 491–504.
5. Starik, A.M., Loukhovitski, B.I., Sharipov, A.S., Titova, N.S., “Intensification of shock-induced combustion by electric-discharge-excited oxygen molecules: numerical study,” Com-bust. Theory Model., 2010, Vol. 14, Pp. 653–679. 830.2010.499966
6. Starikovskiy, A., Aleksandrov, N., “Plasma-assisted ignition and combustion,” Prog. Energy Combust. Sci., 2013, Vol. 39, Pp. 61–110.
7. Synthesis Gas Combustion: Fundamentals and Applications ed. by Lieuwen, T.C., Yang, V., Yetter, R.A. (CRC Press, Taylor & Francis Group, Boca Raton, FL, 2009)
8. Starik, A.M., Sharipov, A.S., Titova, N.S., “Intensification of syngas ignition through the exci-tation of CO molecule vibrations: a numerical study,” J. Phys. D: Appl. Phys., 2010, Vol. 43, P. 245501 (14pp).
9. Arsentiev, I.V., “On the influence of discharge parameters on the kinetics of plasma-assisted combustion of synthesis gas in air,” Physical-Chemical Kinetics in Gas Dynamics, in press.
10. Losev, S.A., “Physical-chemical processes in thermal nonequilibrium gases,” Physical-Chemical Kinetics in Gas Dynamics, 2012, Vol. 12, No. 1.
11. Lament, C., George, T., Meister, K.A., Tufts, J.C., Rich, J.W., Subramaniam, V.V., Martin, J.-P., Piar, B., Perrin, M.-Y., “Nonequilibrium vibrational kinetics of carbon monoxide at high translational mode temperatures,” Chem. Phys., 1992, Vol. 163, Pp. 241-262.
12. Plonjes, E., Palm, P., Chernukho, A.P., Adamovich, I.V., Rich, J.W., “Time-resolved Fourier transform infrared spectroscopy of optically pumped carbon monoxide,” Chem. Phys., 2000, Vol. 256, Pp. 315–331.
13. Lee, W., Adamovich, I.V., Lempert, W.R., “Optical pumping studies of vibrational energy transfer in high-pressure diatomic gases,” J. Chem. Phys., 2001, Vol. 114, Pp. 1178-1186.
14. Plonjes, E., Palm, P., Lee, W., Chidley, M.D., Adamovich, I.V., Lempert, W.R., Rich, J.W., “Vibrational energy storage in high pressure mixtures of diatomic molecules,” Chem. Phys., 2000, Vol. 260, Pp. 353–366.
15. Huber K.P., Herzberg. G. Molecular spectra and molecular structure. IV. Constants of diatomic molecules (Van Nostrand, New York, 1979). P. 716.
16. Kustova, E.V., Savelev, A.S., Lukasheva, A.A, “Refinement of state-resolved models for chemical kinetics using the data of trajectory calculations,” Physical-Chemical Kinetics in Gas Dynamics, 2012, Vol. 12, No. 1.
17. Adamovich, I.V., Macheret, S.O., Rich, W.J., Treanor, C.E., “Vibrational energy transfer rate using force harmonic oscillator model,” J. Thermophys. Heat Transfer., 1998, Vol. 12, Pp. 57–65.
18. Millikan, R.C., White, D.R., “Systematics of Vibrational Relaxation,” J. Chem. Phys., 1963, Vol. 39, P. 3209.
19. Kadochnikov, I.N., Loukhovitski, B.I., Starik, A.M., “Thermally non-equilibrium effects in shock-induced nitrogen plasma: modelling study,” Plasma Sources Sci. Technol., 2013, Vol. 22, P. 035013.
20. Langhoff, S.R., Bauschlicher, C.W., “Global dipole moment function for the X1Σ+ ground state of CO,” J. Chem. Phys., 1995, Vol. 102, Pp. 5220-5225.
21. Ionin, A.A., “Electric discharge CO lasers” in Gas Lasers ed. by Endo. M., Walter, R.F. (CRC Press, Taylor and Francis, Boca Raton, Florida, USA, 2007). Pp. 201–237.
22. Glass, G.P., Klronde, S., “Vibrational Relaxation of Carbon Monoxide in Collisions with Atomic Hydrogen,” J. Phys. Chem., 1982, Vol. 86, Pp. 908-913.
23. Blauer, J.A., Nickerson, G.R., “A survey of vibrational relaxation rate data for processes im-portant to CO2-N2-H2O infrared plume radiation,” 7th Fluid and PlasmaDynamics Conference, AIAA Paper 1974-536 (1974).