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Wang & Rutland (2005): Temp & :math:`\phi` effects on ignition of n-heptane spray
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**Title**

Effects of temperature and equivalence ratio on the ignition of :math:`n`-heptane fuel spray in turbulent flow


**Authors**

Y. Wang, and C. J. Rutland


**Summary**


  DNS was performed to study the autoignition process of :math:`n`-heptane fuel spray in the isotropic turbulent field. Finally, a correlation was derived relating ignition delay times to temperature and equivalence ratio.

- Euler-Lagrangian approach

- :math:`n`-heptane with 44 species and 112 reactions

- Different initial temperature and equivalence ratio.


(1) Effect of initial temperature

- Temperature decrerases at first due to evaporation.

- There is an additional slight temperature decrease due to direct decomposition and atomic hydrogen abstraction of :math:`n`-heptane.

- After evaporation, there is an another period of very slight temperature increase due to ``cool flame`` chemistry, including the production of CO: This period is an ignition delay between initial fuel decomposition and very rapid heat global temperature rise.


(2) Effect of equivalence ratio

  Adopted :math:`\phi`: 0.5, 1.0 and 1.5 with same initial temperature of 1300 K.

- The effect of increasing the global equivalence ratio is to add more spray particles, increasing the evaporative colling so that the ignition delay is increased.