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Zel'dovich mechanism

Zel'dovich mechanism is a chemical mechanism that describes the oxidation of nitrogen and NOx formation, first proposed by the Russian scientists Yakov Borisovich Zel'dovich, David A. Frank-Kamenetskii and P. Ya. Sadovnikov in 1947.[1][2][3] The reaction mechanisms read as

where and are the reaction rate constants in Arrhenius law. The overall global reaction is given by

The overall reaction rate is mostly governed by the first reaction (i.e., rate-determining reaction), since the second reaction is much faster than the first reaction and occurs immediately following the first reaction. At fuel-rich conditions, due to the lack of oxygen, reaction 2 becomes weaker, but instead influenced by a third reaction, also known as extended Zel'dovich mechanism (with all three reactions),[4][5]

The forward rate constants of the reactions are given by[6]

where the pre-exponential factor is measured in units of cm, mol, s and K, temperarure in kelvins, and the activation energy in cal/mol; R is the universal gas constant.

NO formationEdit

The rate of NO concentration is given by



  1. ^ Zeldovich, Y. A., D. Frank-Kamenetskii, and P. Sadovnikov. Oxidation of nitrogen in combustion. Publishing House of the Acad of Sciences of USSR, 1947.
  2. ^ Williams, Forman A. "Combustion theory". (1985).
  3. ^ Zeldovich, I. A., Barenblatt, G. I., Librovich, V. B., Makhviladze, G. M. (1985). Mathematical theory of combustion and explosions.
  4. ^ Lavoie, G. A., Heywood, J. B., Keck, J. C. (1970). Experimental and theoretical study of nitric oxide formation in internal combustion engines. Combustion science and technology, 1(4), 313–326.
  5. ^ Hanson, R. K., Salimian, S. (1984). Survey of rate constants in the N/H/O system. In Combustion chemistry (pp. 361–421). Springer, New York, NY.
  6. ^ "San Diego Mechanism".