Multi-modal counterflow flame structure under autoignitive conditions

Temistocle Grenga, Michael E. Mueller

Research output: Contribution to conferencePaper

Abstract

In practical systems, combustion does not occur in asymptotic limits of nonpremixed flames, premixed flames, or autoignition but rather multiple modes that interact. In canonical configurations, multi-modal combustion is critical in the stabilization of lifted jet flames. At low temperature conditions, such flames are stabilized by a 'triple' flame consisting of regions of premixed and nonpremixed combustion. At high temperature conditions, autoignition is activated, and the role of autoignition versus premixed flame propagation in flame stabilization depends on the local residence time and the local flow speed. While detailed simulations of laminar lifted jet flames are computationally tractable, extension to DNS of turbulent lifted jet flames at reasonable Reynolds numbers is computationally intractable due to the large domain size required. Therefore, the counterflow configuration is investigated as a more compact alternative. In this work, a series of detailed simulations of DME/air laminar counterflow flames at elevated pressure are performed with variations in the stream compositions, temperatures, and velocities to provide flames spanning different combinations of combustion modes, specifically a nonpremixed flame, a 'triple' flame, and a series of flames with all three modes interacting. Similarities and differences between the counterflow flames and the lifted jet flames are explored.

Original languageEnglish (US)
StatePublished - Jan 1 2017
Event10th U.S. National Combustion Meeting - College Park, United States
Duration: Apr 23 2017Apr 26 2017

Other

Other10th U.S. National Combustion Meeting
CountryUnited States
CityCollege Park
Period4/23/174/26/17

All Science Journal Classification (ASJC) codes

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

Keywords

  • Counterflow
  • DME
  • Multi-modal combustion

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  • Cite this

    Grenga, T., & Mueller, M. E. (2017). Multi-modal counterflow flame structure under autoignitive conditions. Paper presented at 10th U.S. National Combustion Meeting, College Park, United States.