engleski

Cool-flame auto-ignition of automotive fuels in the ECFM-3Z combustion model

In this paper the recent efforts of implementing cool flame auto-ignition tabulated data into AVL code "FIRE" will be presented, focused on n- heptane as fuel. Current use of n-heptane in combustion simulations did not include the phenomenon of cool flame ignition, and taking it into account could improve simulations of combustion in IC engines, and also with wider application spectrum. The methodology of the ignition tabulation procedure presented here has also been proven to work well with different types of fuels. Current methods of auto-ignition computation in AVL code "FIRE" (used in Extended Coherent Flame Model with three zones approach (ECFM-3Z) combustion model) are based on the extraction of ignition delay times from tabulated data dependent on four parameters: temperature, pressure, air excess ratio and EGR mass fraction. The methods described here were used for creation of the new extended tables which included cool flame delays using Chemkin package and a more comprehensive chemical mechanism. The methods and ideas behind implementing the cool flame data into the ECFM- 3Z model will also be presented, as well as a comparison between the temperature evolutions calculated with ECFM-3Z model on a simple 100 cell mesh and a standalone application using Chemkin package showing improvement on prediction of both the cool-flame ignition and overall temperature distribution.

ECFM-3Z; auto-ignition; n-heptane; tabulation

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