Nonlinear Dynamics Of Laboratory Combustor Pressure Oscillations

Abstract

The mechanisms responsible for driving and damping of pressure oscillations in a laboratory combustor have been investigated. The chamber contains a turbulent methane/hydrogen/air premixed flame stabilized behind a rearward-facing step. Shadowgraph cinematography reveals the shedding of large vortices from the step at frequencies of the system acoustic modes. Variations in the fuel equivalence ratio and the mean flow speed result in a wide variety of nonlinear dynamical behavior. Typically, large cycle-to-cycle variations are observed such that energy may be added or subtracted over one cycle of oscillation but zero net energy change occurs many cycles of oscillation. A quantitative version of Rayleigh's Criterion is constructed by using the cross-spectral-density of the measured flame radiation and pressure. The results under one set of operating conditions show that large driving near the flameholder is balanced by equally large damping further downstream. A second set of conditions results in large energy addition to an acoustic mode balanced by attenuation at the mode subharmonic. © 1991, Taylor & Francis Group, LLC. All rights reserved.

Department(s)

Business and Information Technology

Second Department

Chemical and Biochemical Engineering

Comments

Air Force Office of Scientific Research, Grant None

Keywords and Phrases

Combustion instabilities Rayleigh's; criterion Dynamical systems

International Standard Serial Number (ISSN)

1563-521X; 0010-2202

Document Type

Article - Journal

Document Version

Citation

File Type

text

Language(s)

English

Rights

© 2025 Taylor and Francis Group; Taylor and Francis; Combustion Institute, All rights reserved.

Publication Date

01 Jun 1991

Link to Full Text

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