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Experiments and Modeling of Impinging Jets and Premixed Hydrocarbon Stagnation Flames

Citation

Bergthorson, Jeffrey Myles (2005) Experiments and Modeling of Impinging Jets and Premixed Hydrocarbon Stagnation Flames. Dissertation (Ph.D.), California Institute of Technology. doi:10.7907/7FQZ-EY88. https://resolver.caltech.edu/CaltechETD:etd-05242005-165713

Abstract

To model the combustion of long-chain hydrocarbon fuels, an accurate kinetics mechanism must first be developed for the oxidation of small hydrocarbons, such as methane, ethane, and ethylene. Even for methane, a generally accepted mechanism is still elusive due to a lack of kinetically independent experimental data. In this work, a combined experimental and modeling technique is developed to validate and further optimize these mechanisms. This technique relies on detailed measurements of strained flames in a jet-wall stagnation flow using simultaneous Particle Streak Velocimetry (PSV) and CH Planar Laser Induced Fluorescence (PLIF). Stagnation flames are simulated using an axisymmetric, one-dimensional model with accurate specification of the requisite boundary conditions. Direct comparisons between experiment and simulation allow for an assessment of the various models employed, with an emphasis on the chemistry model performance.

The flow field for a cold impinging laminar jet is found to be independent of the nozzle-to-plate separation distance if velocities are scaled by the Bernoulli velocity. The one-dimensional formulation is found to accurately model the stagnation flow if the velocity boundary conditions are appropriately specified. The boundary-layer-displacement-thickness corrected diameter is found to be an appropriate scale for axial distances and allows the identification of an empirical, analytical expression for the flow field of the impinging laminar jet.

Strained methane-air flame experiments confirm that the reacting flow is also independent of the nozzle-to-plate separation distance. Methane, ethane, and ethylene flames are studied as functions of the applied strain rate, mixture dilution, and mixture fraction. Mechanism performance is found to be relatively insensitive to both the mixture dilution and the imposed strain rate, while exhibiting a stronger dependence on the fuel type and flame stoichiometry. The approach and diagnostics presented here permit an assessment of the predictions of strained-hydrocarbon flames for several combustion chemistry mechanisms. The data presented in this thesis are made available to kineticists looking for optimization targets, with the goal of developing a predictive kinetics model for hydrocarbon fuels. The methodology described here can allow new optimization targets to be rapidly measured, reducing the experimental burden required to fully constrain the chemistry models.

Item Type:Thesis (Dissertation (Ph.D.))
Subject Keywords:CH; chemical kinetics; combustion; ethane; ethylene; methane; modeling; Particle Streak Velocimetry; Planar Laser Induced Fluorescence; PLIF; PSV; stagnation flow
Degree Grantor:California Institute of Technology
Division:Engineering and Applied Science
Major Option:Aeronautics
Minor Option:Chemistry
Awards:William F. Ballhaus Prize, 2005. Charles D. Babcock Award, 2003.
Thesis Availability:Public (worldwide access)
Research Advisor(s):
  • Dimotakis, Paul E.
Group:GALCIT
Thesis Committee:
  • Dimotakis, Paul E. (chair)
  • Kuppermann, Aron
  • Meiron, Daniel I.
  • Goodwin, David G.
  • Shepherd, Joseph E.
Defense Date:26 May 2005
Funders:
Funding AgencyGrant Number
Air Force Office of Scientific Research (AFOSR)UNSPECIFIED
Caltech Northrop ChairUNSPECIFIED
Record Number:CaltechETD:etd-05242005-165713
Persistent URL:https://resolver.caltech.edu/CaltechETD:etd-05242005-165713
DOI:10.7907/7FQZ-EY88
Related URLs:
URLURL TypeDescription
http://resolver.caltech.edu/CaltechETD:etd-05302008-113043Related DocumentEngineer's thesis for Laurent Jean-Michel Benezech (2008)
ORCID:
AuthorORCID
Bergthorson, Jeffrey Myles0000-0003-2924-7317
Default Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:2004
Collection:CaltechTHESIS
Deposited By: Imported from ETD-db
Deposited On:27 May 2005
Last Modified:12 Aug 2020 22:53

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