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Effect of stretch on the burning velocity of laminar and turbulent premixed flames

Zirwes, Thorsten

Abstract (englisch):
Steady and unsteady laminar premixed methane/air and hydrogen/air plane-jet flames with different equivalence ratios ranging from fuel-lean to fuel-rich are investigated under atmospheric conditions using DNS with detailed molecular transport and chemistry. The objective is to gain a deeper understanding of the influence of unsteady and nonuniform stretching on flame propagation.

A nonuniform velocity profile used at the inlet leads to a stretched flame. For steady-state flames, consumption speeds, flame stretch, curvature, strain and Markstein numbers are evaluated. By increasing the mass flow rate at the inlet, the flames become longer and different Markstein numbers are obtained.

The inflow is then harmonically excited with different frequencies and the flames oscillate in the unsteady flow. For these unsteady flames, flame relaxation times are evaluated from the phase shift between the movement of the flame and the fluid flow velocity at the flame surface. The amplitude of the flame front movement is attenuated with increasing frequency and chemical time scale. Also, the phase shift between the movement of the flame and the local flow field becomes larger with increasing frequency or chemical time scale. ... mehr

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Volltext §
DOI: 10.5445/IR/1000094585
Veröffentlicht am 15.05.2019
Cover der Publikation
Zugehörige Institution(en) am KIT Engler-Bunte-Institut (EBI)
Publikationstyp Hochschulschrift
Publikationsjahr 2016
Sprache Englisch
Identifikator KITopen-ID: 1000094585
Verlag Karlsruher Institut für Technologie (KIT)
Umfang XII, 87 S.
Art der Arbeit Abschlussarbeit - Master
Externe Relationen Siehe auch
Schlagwörter CFD flame stretch combustion OpenFOAM Cantera laminar turbulent oscillating flames Markstein Karlovitz Direct Numerical Simulation DNS Detailed Multicomponent Diffusion
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