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Title: Numerical prediction of turbulent flame stability in premixed/prevaporized (HSCT) combustors. Final Report, 1 Apr. 1989 - 31 Dec. 1990

Abstract

A numerical analysis of combustion instabilities that induce flashback in a lean, premixed, prevaporized dump combustor is performed. KIVA-II, a finite volume CFD code for the modeling of transient, multidimensional, chemically reactive flows, serves as the principal analytical tool. The experiment of Proctor and T'ien is used as a reference for developing the computational model. An experimentally derived combustion instability mechanism is presented on the basis of the observations of Proctor and T'ien and other investigators of instabilities in low speed (M less than 0.1) dump combustors. The analysis comprises two independent procedures that begin from a calculated stable flame: The first is a linear increase of the equivalence ratio and the second is the linear decrease of the inflow velocity. The objective is to observe changes in the aerothermochemical features of the flow field prior to flashback. It was found that only the linear increase of the equivalence ratio elicits a calculated flashback result. Though this result did not exhibit large scale coherent vortices in the turbulent shear layer coincident with a flame flickering mode as was observed experimentally, there were interesting acoustic effects which were resolved quite well in the calculation. A discussion of the k-e turbulence modelmore » used by KIVA-II is prompted by the absence of combustion instabilities in the model as the inflow velocity is linearly decreased. Finally, recommendations are made for further numerical analysis that may improve correlation with experimentally observed combustion instabilities.« less

Authors:
Publication Date:
Research Org.:
Maine Univ., Orono, ME (United States)
OSTI Identifier:
5888238
Report Number(s):
N-92-11161; NASA-CR-188991; NAS-1.26:188991
CNN: NAG3-1033
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; COMBUSTION KINETICS; NUMERICAL ANALYSIS; BOUNDARY LAYERS; COMBUSTION CHAMBERS; FINITE ELEMENT METHOD; FLAMES; TURBULENT FLOW; VORTICES; CHEMICAL REACTION KINETICS; FLUID FLOW; KINETICS; LAYERS; MATHEMATICS; NUMERICAL SOLUTION; REACTION KINETICS; 421000* - Engineering- Combustion Systems

Citation Formats

Winowich, N S. Numerical prediction of turbulent flame stability in premixed/prevaporized (HSCT) combustors. Final Report, 1 Apr. 1989 - 31 Dec. 1990. United States: N. p., 1990. Web.
Winowich, N S. Numerical prediction of turbulent flame stability in premixed/prevaporized (HSCT) combustors. Final Report, 1 Apr. 1989 - 31 Dec. 1990. United States.
Winowich, N S. 1990. "Numerical prediction of turbulent flame stability in premixed/prevaporized (HSCT) combustors. Final Report, 1 Apr. 1989 - 31 Dec. 1990". United States.
@article{osti_5888238,
title = {Numerical prediction of turbulent flame stability in premixed/prevaporized (HSCT) combustors. Final Report, 1 Apr. 1989 - 31 Dec. 1990},
author = {Winowich, N S},
abstractNote = {A numerical analysis of combustion instabilities that induce flashback in a lean, premixed, prevaporized dump combustor is performed. KIVA-II, a finite volume CFD code for the modeling of transient, multidimensional, chemically reactive flows, serves as the principal analytical tool. The experiment of Proctor and T'ien is used as a reference for developing the computational model. An experimentally derived combustion instability mechanism is presented on the basis of the observations of Proctor and T'ien and other investigators of instabilities in low speed (M less than 0.1) dump combustors. The analysis comprises two independent procedures that begin from a calculated stable flame: The first is a linear increase of the equivalence ratio and the second is the linear decrease of the inflow velocity. The objective is to observe changes in the aerothermochemical features of the flow field prior to flashback. It was found that only the linear increase of the equivalence ratio elicits a calculated flashback result. Though this result did not exhibit large scale coherent vortices in the turbulent shear layer coincident with a flame flickering mode as was observed experimentally, there were interesting acoustic effects which were resolved quite well in the calculation. A discussion of the k-e turbulence model used by KIVA-II is prompted by the absence of combustion instabilities in the model as the inflow velocity is linearly decreased. Finally, recommendations are made for further numerical analysis that may improve correlation with experimentally observed combustion instabilities.},
doi = {},
url = {https://www.osti.gov/biblio/5888238}, journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 1990},
month = {Mon Jan 01 00:00:00 EST 1990}
}

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