Heat release timing in a nonpremixed Helmholtz pulse combustor

Tang, Yihao; Waldherr, Gregor A.; Jagoda, J.; Zinn, B. T.

doi:10.1016/0010-2180(94)00054-v

Cited by 48 publications

(9 citation statements)

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“…Margolis (1994) analyzed the nonlinear dynamics of a Helmholtz-type pulse combustor and showed that the nonlinear acoustic oscillations arise from the combustion-driven instabilities exciting the acoustic modes. Tang et al (1995) showed the oscillations in a pulse combustor to be a consequence of coupling of several acoustic and hydrodynamic factors. Bloom et al (2005Bloom et al ( , 2010Bloom and Patterson, 2009) studied the nonlinear dynamics of a pulse combustor, but focused their study on valved pulse combustors.…”

Section: Introductionmentioning

confidence: 98%

Dynamic Characterization of a Laboratory-Scale Pulse Combustor

Mondal

Mukhopadhyay

Sen

2014

Combustion Science and Technology

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Pulse combustion is a self-sustained and self-oscillating process driven by combustion, coupled with resonant oscillation of the flow in the tailpipe. This article describes the investigation of the effects of different parameters in a laboratory-scale pulse combustor and analyzes them using concepts of nonlinear dynamics. Two orientations of the fuel injection holes were used. In one orientation, the fuel comes in vertically in parallel and counter-flow with the air stream, while in the other orientation the fuel is injected horizontally at cross-flow with the air stream. For the vertical orientation, the frequency slightly decreased with decrease of global equivalence ratio and inlet flow rate. With change of lean to rich air/fuel mixture, the dynamics changes from non-pulsating to pulsating combustion. The transition from noise-dominated to periodic oscillation has also been verified by evaluating the correlation dimension. In the horizontal orientation of the fuel inlet, the pulsating behavior has been obtained even under fuel-lean conditions due to better mixing of air and fuel, and phase and fast Fourier transform plots indicate quasi-periodic behavior.

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Section: Introductionmentioning

confidence: 98%

Dynamic Characterization of a Laboratory-Scale Pulse Combustor

Mondal

Mukhopadhyay

Sen

2014

Combustion Science and Technology

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“…At a frequency of 10Hz they observed a reduction in the overall flame length. Other research involving acoustic excitation or feedback has been conducted with both non-premixed and premixed flames in ramjets (Reuter et al, 1990), pulsed combustors (Tang et al, 1995b, Reuter et al, 1986, and other ducts (Chen et al, 1993, Hegde et al, 1988. Each of these combustor configurations is however characterized by a strong coupling between the combustion process and the acoustic field.…”

Section: Please Scroll Down For Articlementioning

confidence: 98%

Structure and Flame Length of Fully-Modulated, Turbulent Diffusion Flames

Hermanson

Dugnani

Johari

2000

Combustion Science and Technology

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The turbulent flame structure and flame length of fully-modulated diffusion flames was examined over a range of pulsing frequencies, injection flow rates, and duty-cycles. An injection system employing an electronically-controlled solenoid value was used to discharge puffs of unheated natural gas and ethylene fuel into still air at one atmosphere pressure. Video imaging of the luminosity from the sooting regions of the flame revealed two distinct types of flame structure. For small injected volumes and short injection times, compact, puff-like structures with a short flame length were generated. More elongated "cigar-shaped" structures, with a longer flame length closer to that of steady-state flames, resulted from longer injection times and larger injected volumes. An injection parameter which characterizes the transition from puff-like to cigar-shaped flame behavior is presemed. For puffs, an increase in duty-cycle generally led to an increase in flame length. This increase was less for cigar-shaped flames. The downstream location of the puff-like flame structures increased roughly with time to the 1/2 power, in agreement with buoyant thermals and starting jets.

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“…Consequently, the ratio of the amplitude of the velocity oscillation to the mean velocity B can be obtained at each local position. Then the local heat transfer in a pulsating flow can be predicted using equation (9).…”

Section: Theoretical Studiesmentioning

confidence: 99%