NTC-affected ignition in nonpremixed counterflow

Chung King Law, Peng Zhao

Research output: Chapter in Book/Report/Conference proceedingConference contribution

1 Scopus citations

Abstract

Using n-heptane as the model fuel, the role of the Negative Temperature Coefficient (NTC) chemistry on ignition is computationally studied for both homogeneous mixtures and nonpremixed counterflow. For homogeneous mixtures, results show that ignition occurs in two-stages within the NTC temperature regime, with the duration and temperature increment decreasing with increasing initial temperature for the first ignition stage, leading to increased duration of the second ignition stage and thereby the observed NTC-behavior. For the nonpremixed counterflow, results show that a secondary S-curve is developed on the lower branch of the conventional, primary S-curve for sufficiently low strain rates and/or sufficiently high pressures, with its own distinct ignition-extinction turning points. Sensitivity analysis and Chemical Explosive Mode Analysis (CEMA) show that this secondary S-curve is controlled by the low-temperature NTC-chemistry, with heat release negligible for states on its lower branch and discernable for states on its upper branch and hence assuming the characteristics of a weakly-burning flame. The possible existence of one- and two-staged ignition in the counterflow is observed, and its dependence on the flow strain rate and system pressure are identified.

Original languageEnglish (US)
Title of host publicationFall Technical Meeting of the Eastern States Section of the Combustion Institute 2011
PublisherCombustion Institute
Pages349-373
Number of pages25
ISBN (Electronic)9781622761258
StatePublished - Jan 1 2011
EventFall Technical Meeting of the Eastern States Section of the Combustion Institute 2011 - Storrs, United States
Duration: Oct 9 2011Oct 12 2011

Publication series

NameFall Technical Meeting of the Eastern States Section of the Combustion Institute 2011

Other

OtherFall Technical Meeting of the Eastern States Section of the Combustion Institute 2011
CountryUnited States
CityStorrs
Period10/9/1110/12/11

All Science Journal Classification (ASJC) codes

  • Physical and Theoretical Chemistry
  • Mechanical Engineering
  • Chemical Engineering(all)

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  • Cite this

    Law, C. K., & Zhao, P. (2011). NTC-affected ignition in nonpremixed counterflow. In Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2011 (pp. 349-373). (Fall Technical Meeting of the Eastern States Section of the Combustion Institute 2011). Combustion Institute.