A Comparison of Several Theories which Use Jet Scaling to Predict Liftoff Heights of Turbulent-Jet Flames,

Abstract

In this paper several previously developed theories for predicting liftoff heights of turbulent-jet flames are examined and compared. The five theories are: a turbulent flame speed theory, a cascade mixing time theory, a strain-rate theory, a scalar dissipation-rate theory and an empirical correlation. Each theory uses far-field scaling of isothermal, turbulent jets. Through a systematic algebraic development, the predictions of the theories are presented in a common form. They are then compared for their ability to predict the experimentally observed linear dependence of liftoff height on nozzle exit velocity. Following this, their ability to correctly predict the relative liftoff heights of different fuels is examined. Finally, the theories are extended to predict blowout and their predictions are compared to experimental results of several fuels.

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Document Details

Document Type
Technical Report
Publication Date
Dec 31, 1990
Accession Number
ADA239717

Entities

People

  • Jay A. Hammer

Organizations

  • California Institute of Technology

Tags

Communities of Interest

  • C4I

DTIC Thesaurus Topics

  • Aeronautical Laboratories
  • California
  • Classification
  • Diffusion
  • Dissipation
  • Equations
  • Far Field
  • Flames
  • Fluid Mechanics
  • Jet Flames
  • Mixing
  • Payload
  • Strain Rate
  • Thermal Conductivity
  • Transport Properties
  • Turbulent Mixing
  • Two Dimensional

Fields of Study

  • Physics

Readers

  • Combustion science or combustion engineering.
  • Computational Fluid Dynamics (CFD)
  • Theoretical Analysis.