PDF Modeling of Turbulent Combustion

Abstract

In both space and aircraft applications, the design of combustors in propulsion systems remains a significant technical challenge. Given the cost, difficulty and time consumed in experimental testing, it is well recognized that computer modeling is essential to exploring different design concepts, and to reducing the cost and time of the design cycle. While many phenomena may be involved - sprays, radiation, combustion dynamics, etc. - a central problem is that of modeling turbulent-chemistry interactions in turbulent combustion. The PDF approach to turbulent combustion has the advantages of fully representing the turbulent fluctuations of species and temperature, and of allowing realistic combustion chemistry to be implemented (e.g., of order 50 species). This methodology is also being applied in conjunction with large-eddy simulations, in which case it is referred to as LES/FDF. The overall objective of the proposed work is to advance and extend the PDF and LES/FDF approaches to modeling turbulent combustion in flows of relevance to aerospace propulsion systems. Currently, PDF methods are being applied to flames in vitiated co-flows, both lifted methane non-premixed flames and also attached piloted premixed flames. In future work, the LES/FDF approach will be applied to piloted jet flames and to bluff-body jet flames. This will enable a three-way comparison between experimental data, the LES/FDF calculations, and previous PDF calculations. In all of these calculations, realistic and reliable combustion chemistry is used (e.g., involving of order 20-50 species) so that turbulence-chemistry interactions such as local extinction and re-ignition can be investigated. Collaboration with the University of Pittsburgh continues and has resulted in one of the first LES/PDF calculations of a turbulent flame (Sheikhi et al. 2005).

Open PDF

Document Details

Document Type
Technical Report
Publication Date
Jun 01, 2006
Accession Number
ADP023647

Entities

People

  • Stephen B. Pope

Organizations

  • Sibley School of Mechanical and Aerospace Engineering

Tags

Communities of Interest

  • Space

DTIC Thesaurus Topics

  • Air Force
  • Chemistry
  • Combustion
  • Combustion Products
  • Computational Fluid Dynamics
  • Computations
  • Decomposition
  • Experimental Data
  • Extinction
  • Fluid Dynamics
  • Ignition
  • Jet Flames
  • Large Eddy Simulation
  • Parallel Computing
  • Propulsion Systems
  • Simulations
  • Turbulent Mixing

Fields of Study

  • Physics

Readers

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

Technology Areas

  • Space
  • Space - Hall-Effect Thruster