Stationary edge flames in a wedge with hydrodynamic variable-density interaction

Shields, Benjamin Thomas

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https://hdl.handle.net/2142/108502 Copy

Description

Title

Stationary edge flames in a wedge with hydrodynamic variable-density interaction

Author(s)

Shields, Benjamin Thomas

Issue Date

2020-07-16

Director of Research (if dissertation) or Advisor (if thesis)

• Freund, Jonathan B
• Pantano, Carlos

Doctoral Committee Chair(s)

Freund, Jonathan B

Committee Member(s)

• Fischer, Paul
• Panesi, Marco

Department of Study

Mechanical Sci & Engineering

Discipline

Theoretical & Applied Mechans

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• Combustion
• Edge Flame
• Ethylene
• Nonpremixed

Abstract

Edge flames are a canonical two-dimensional flame structure appearing in more complicated combustion problems, such as lifted jet flames and in the dynamics of the growth and repair of flame holes in nonpremixed turbulent combustion. Typical theoretical configurations to study edge flames are unable to evaluate retreating edge flames with strong hydrodynamic-coupling. A new computational configuration is introduced which places the edge flame in a wedge-shaped counterflow with a mass sink, providing control over the position of the edge flame, and allowing access to stationary, hydrodynamically-coupled retreating flames (at high strain). This framework is first used to evaluate edge flames using a simple global one-step chemistry model and Fickian transport. This simple model is used to characterize the behavior of the resulting edge flames, including the relationship between flame speed and transverse strain rate and response to Lewis number variations. The details of the computational method will be discussed, including the underlying finite element method, the generation of boundary data, and the continuation of the flame through regions of varying transverse strain. This configuration is then applied to detailed ethylene-air combustion using a skeletal reduction of the USC Mech II combustion reaction model and a detailed transport model. The details of the ethylene-air edge flame are discussed, and comparisons are made between stoichiometric, fuel-lean, and fuel-rich compositions. Novel results characterizing the dilatation and vorticity near the flame front are provided, data which are necessary for the construction of potential flow approximations of hydrodynamically-coupled edge flames.

Graduation Semester

2020-08

Type of Resource

Thesis

Permalink

http://hdl.handle.net/2142/108502

Copyright and License Information

Copyright 2020 Benjamin Thomas Shields

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