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Combustion pp 131-146 | Cite as

Ignition Processes

  • Jürgen Warnatz
  • Ulrich Maas
  • Robert W. Dibble

Abstract

The discussion of premixed flames (Chapter 8) and nonpremixed flames (Chapter 9) assumed that the flames were at a steady state. The solutions are time-independent. The time-dependent process of starting with reactants and evolving in time towards a steadily burning flame is called ignition. Ignition processes are always time-dependent. Examples of ignition processes include induced ignition (such as occurs in gasoline engines induced by a spark), autoignition (such as occurs in Diesel engines), and photoignition caused by photolytic generation of radicals. In these cases, the ignition process is described quantitatively by addition to the time-dependent energy conservation equation (3.6) a term ∂p/∂t,
$$\rho {c_p}\frac{{\partial T}}{{\partial t}} = \frac{{\partial p}}{{\partial t}} + \frac{\partial }{{\partial z}}(\lambda \frac{{\partial T}}{{\partial z}}) - \left( {\rho v{c_p} + \sum\limits_j {{j_j}{c_{p,j}}} } \right)\frac{{\partial T}}{{\partial z}} - \sum\limits_j {{h_j}{r_j}} . $$
(10.1)
.

Keywords

Heat Production Flame Propagation Thermal Explosion Premix Flame Ignition Delay Time 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

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Copyright information

© Springer-Verlag Berlin Heidelberg 1996

Authors and Affiliations

  • Jürgen Warnatz
    • 1
  • Ulrich Maas
    • 2
  • Robert W. Dibble
    • 3
  1. 1.Interdisziplinäres Zentrum für Wissenschaftliches RechnenUniversität HeidelbergHeidelbergGermany
  2. 2.Konrad-Zuse-Zentrum für InformationstechnikBerlinGermany
  3. 3.Dept. of Mechanical EngineeringUniversity of CaliforniaBerkeleyUSA

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