High-fidelity simulations and modeling of compressible reacting flows

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Abstract/Contents

Abstract
Scramjets are air-breathing propulsion devices and have long been recognized as suitable for hypersonic propulsion. Because of the high speed in scramjet combustors, the flow has a very short residence time before leaving the engine, during which air and fuel must mix on a molecular level and chemical reactions have to be completed. Although some ground and flight experiments have successfully demonstrated the feasibility of supersonic combustion, experimental testing requires a large investment and presents numerous difficulties. Computational tools are thus a key element toward the development of an efficient, high-performance scramjet engine, and because mixing and heat release are at the heart of a scramjet operation, the development and use of accurate combustion models for supersonic combustion are critical. The open questions in supersonic combustion span the spectrum from scientific pursuit, e.g., shock/flame interactions, to engineering applications like prediction of unstart phenomena in scramjets. In this study, direct numerical simulations (DNS) of a compressible reacting mixing layer with finite rate chemistry are performed. The DNS databases are used to explore the physics of supersonic combustion. An efficient combustion model based on the flamelet/progress variable is then introduced. In this approach, only two or three additional scalar transport equations need to be solved, independently of the complexity of the reaction mechanism. The proposed combustion model is validated using DNS databases. Finally, the compressible flamelet/progress variable model is applied to the case of an under-expanded hydrogen jet in a supersonic cross-flow and HIFiRE scramjet.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2014
Issuance monographic
Language English

Creators/Contributors

Associated with Saghafian, Amirreza
Associated with Stanford University, Department of Mechanical Engineering.
Primary advisor Pitsch, Heinz
Thesis advisor Pitsch, Heinz
Thesis advisor Ihme, Matthias
Thesis advisor Moin, Parviz
Advisor Ihme, Matthias
Advisor Moin, Parviz

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Amirreza Saghafian.
Note Submitted to the Department of Mechanical Engineering.
Thesis Thesis (Ph.D.)--Stanford University, 2014.
Location electronic resource

Access conditions

Copyright
© 2014 by Amirreza Saghafian
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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