Premixed Turbulent Combustion in High Reynolds Number Regimes of Thickened Flamelets and Distributed Reactions

Abstract

The physics of turbulent premixed flames, in the range of the high Reynolds numbers that are associated with Air Force applications, was measured for the first time using advanced laser imaging diagnostics. Combustion in three regimes on the Borghi regime diagram of premixed turbulent flames was quantified for the first time, by imaging the thicknesses of preheat and reaction layers. New PLIF diagnostics were developed, due to our interactions with Dr. Cam Carter at AFRL to image reactions zones with a new CH PLIF method, as well as using the overlap method that involves formaldehyde and OH PLIF. Results are used to assess previous theoretical predictions of regime boundaries. PLIF images of CH, OH and formaldehyde were obtained for thirteen cases. The three regimes are (a) the thickened preheat (TP) regime that is bounded by the Klimov-Williams limit, (b) the broken reaction layers (BR) boundary and the partially-distributed reactions (PDR) regime. A new Hi-Plot burner provides "extremely-turbulent" flames which is ten times the turbulence level of previous experiments.

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Document Details

Document Type
Technical Report
Publication Date
Mar 24, 2016
Accession Number
ADA631885

Entities

People

  • James F. Driscoll

Organizations

  • University of Michigan

Tags

Communities of Interest

  • Air Platforms
  • C4I
  • Space

DTIC Thesaurus Topics

  • Air Force
  • Air Force Research Laboratories
  • Boundaries
  • Chemical Reactions
  • Chemistry
  • Combustion
  • Dye Lasers
  • Electronic Mail
  • Formaldehyde
  • Geometry
  • Ignition Lag
  • Measurement
  • Physics
  • Reynolds Number
  • Thickness
  • Turbulence
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

  • Combustion science or combustion engineering.
  • Fluid Mechanics and Fluid Dynamics.

Technology Areas

  • Directed Energy