Cellular instability in expanding turbulent flames

Zirui Liu, Abhishek Saha, Sheng Yang, Chung K. Law

Research output: Contribution to conferencePaperpeer-review

Abstract

Cellular instability and turbulent eddies both can wrinkle an otherwise smooth laminar flamefront and thereby increase the surface area leading to flame acceleration, which is characteristically controlled by the length and time-scales of the individual processes. In this paper we report a study on turbulent flames over a large range of pressure conditions, where laminar flames are cellularly unstable. The effects of two mechanisms of cellular instabilities, namely Darrieus-Landau and diffusional-thermal instabilities on turbulent flames have been categorically investigated. First, a simple scaling analysis is presented to compare the strength of the instability and turbulence and to show that the classical premixed turbulent flame regime diagram can be subdivided into three regimes of: instability dominated, turbulence dominated and instability-turbulence interaction. Next, we present experimental results from a large range of conditions to show that irrespective of the mode of instability, flame propagation is indeed controlled by cellular instability, turbulence and both in these three regimes respectively. Furthermore, by modulating the mixture Lewis number, hence the strength of the diffusional-thermal instability, we would also demonstrate its role in turbulent flame propagation.

Original languageEnglish (US)
StatePublished - 2018
Event2018 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2018 - State College, United States
Duration: Mar 4 2018Mar 7 2018

Other

Other2018 Spring Technical Meeting of the Eastern States Section of the Combustion Institute, ESSCI 2018
CountryUnited States
CityState College
Period3/4/183/7/18

All Science Journal Classification (ASJC) codes

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

Keywords

  • Cellular instability
  • Turbulent flame

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