The Physical Structure of Turbulent Flames,

Abstract

This paper reports on measurements made in the mixing region of an axisymmetric turbulent propane/air jet issuing from a round nozzle into a low-velocity, low-turbulence intensity, unconfined co-flowing airstream. The exit velocity of the jet fluid and its turbulence intensity are sufficiently low to allow the formation of ring vortices within the mixing layer, bounded, on the inside, by the potential core of the jet and, on the outside, by the secondary airstream. High speed cine films show evidence of formation of vortices and flamelets at the interfaces. The changes in shape, movement and coalescence downstream of the nozzle are examined. Measurements of fluctuating velocity are made by a single particle-counting forwardscatter laser anemometer. Fluctuating temperature is measured with micro-thermocouples with 'in situ' measurement of time constant and direct compensation by digital signal recording and analysis. Variation in location and amplitude of peaks of velocity and temperature traces are directly associated with flame structures recorded by film. Signals from all probes are acquired and processed by PDP-8 and PDP-1103 Digital Equipment Corporation computers.

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Document Details

Document Type
Technical Report
Publication Date
Jan 01, 1979
Accession Number
ADA070008

Entities

People

  • A. J. Yule
  • N. A. Chigier

Organizations

  • University of Sheffield

Tags

Communities of Interest

  • Energy and Power Technologies
  • Materials and Manufacturing Processes
  • Space

DTIC Thesaurus Topics

  • Air Force
  • Anemometers
  • Buoyancy
  • Chemical Reactions
  • Combustion
  • Diffusion
  • Flames
  • Flow
  • Fluid Dynamics
  • Ignition
  • Measurement
  • Power Spectra
  • Reynolds Number
  • Strouhal Number
  • Three Dimensional
  • Turbulence
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

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

Technology Areas

  • Directed Energy