Flame Driving of Longitudinal Instabilities in Dump Type Ramjet Combustors

Hegde, U.; Reuter, D.; Daniel, B.R.; Zinn, B. T.

doi:10.1080/00102208708947075

Cited by 68 publications

(15 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result is similar to that of Worth and Dawson [16] in their study of two interacting bluff-body stabilized flames; the negative curvatures were indicative of more flame cusping events. Studies by Dunstan and co-workers [5,20] showed that local flame-flame 9 interactions with negative curvatures are either counter-normal, tunnel-closure, or pocket burn-outs. This suggests that the inner branches of flames in the current study could display these types of interactions.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

The role of flow interaction in flame–flame interaction events in a dual burner experiment

Tyagi

Boxx

Peluso

et al. 2019

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

A dual burner experiment is used to investigate how flow interactions affect local flame-flame interaction in turbulent premixed flames. The presence of adjacent flows influences the local structure of these flames and understanding the sensitivity of these flames to adjacent flows is essential for multinozzle combustion devices. To study this sensitivity, a high-aspect-ratio Bunsen flame operating at a constant flow velocity is placed adjacent to an identical burner with non-reacting flow at varying velocities. High-speed OH-planar laser induced fluorescence and stereoscopic-particle image velocimetry measurements are performed to capture flame-front locations and velocity fields. A non-rigid image registration technique is used to calculate the local flame-area variations that occur due to topological differences, and conditional statistics are extracted to relate the local behavior to changes observed in the global behavior of the flames. Extracted flame curvatures and time-averaged progress variables conditioned on flame-flame interactions show differences existing in the inner and outer flame branches near the flame-attachment region. Statistics of these results are presented and compared for all test cases.

show abstract

Section: Resultsmentioning

confidence: 99%

“…Studies have shown that flame-flame interactions can cause changes in flame surface area [1,2], local and global consumption speeds [3], and flame topology [4,5]. Interaction between adjacent flames can affect the shape [6,7], static stability, [8] and dynamic stability [9][10][11][12][13] of a turbulent flame.…”

Section: Introductionmentioning

confidence: 99%

The role of flow interaction in flame–flame interaction events in a dual burner experiment

Tyagi

Boxx

Peluso

et al. 2019

Proceedings of the Combustion Institute

View full text Add to dashboard Cite

show abstract

“…A number of previous studies have considered the dynamics of flames in the interaction zone, although the majority of these studies have focused on flames undergoing thermoacoustic instability. Experiments by Reuter and coworkers [1][2][3][4] showed that variations in the amplitude of thermoacoustically-driven flame area fluctuations due to the level of interaction between the two flames could impact the feedback mechanism. The differences in total flame area and the resultant flame area fluctuations in the experiments by Reuter and coworkers is congruent with other two-V-flame experiments from Francois et al [5] and Dunstan et al [6,7].…”

Section: Introductionmentioning

confidence: 99%

Structure of Flames in Flame Interaction Zones

Tyagi

Boxx

Peluso

et al. 2018

2018 AIAA Aerospace Sciences Meeting

View full text Add to dashboard Cite

Two identical burners with variable burner separations are used to investigate the dynamics of interacting flames. The presence of adjacent flames in large scale combustion devices influences the structure and dynamics of the flames, and understanding the sensitivity of flames to these interactions is vital for local and global flame characterization. The behavior of the flame in the interaction zone is dependent on a number of operating parameters, including burner separations, inlet bulk flow velocities, and flame stabilization or flame shape. High-repetion-rate CH* chemiluminescence and OH-planar laser-induced flourescence measurements are performed to obtain the flame structure and flame-front locations. These measurement techniques allow for the determination of how varying fluid-dynamic and geometric parameters change the behavior of these flames in the flame interaction zones. We also quantify global metrics like flame surface density, global consumption speed, and flame curvature PDFs to understand the impact of flame interaction.

show abstract

“…The objective of this research to explore the dynamical processes controlling the response of bluff body stabilized flames to harmonic oscillations. It is motivated by the problem of combustion instabilities in afterburners (Lovett et al [1]), which arise due to complex feedback process between pressure, velocity and heat-release oscillations (Sivakumar and Chakravarthy [2], Hegde et al [3], Poinsot et al [4], Yu et al [5], Balasubramanian and Sujith [6]). Both the flame and the flow are influenced by acoustic excitation; e.g., shear layer rollup and/or vortex shedding frequency events lock into the forcing.…”

Section: Introductionmentioning

confidence: 99%

Vortex Phase-Jitter in Acoustically Excited Bluff Body Flames

Shanbhogue

Seelhorst

Lieuwen

2009

International Journal of Spray and Combustion Dynamics

View full text Add to dashboard Cite

This paper describes an experimental study of the effect of acoustic excitation on bluff body stabilized flames, specifically on the flow field characteristics. The Kelvin-Helmholtz (KH) instability of the shear layer is excited due to the incident acoustics. In turn, the KH instability imposes a convecting, harmonic excitation on the flame, which leads to spatially periodic flame wrinkling and heat-release oscillations. Understanding the factors influencing these heat release oscillations requires an understanding of the generation, convection, and dissipation of these vortical disturbances. Phase locked particle image velocimetry was carried out over a range of conditions to characterize the vortical dynamics. It was found that the vortex core location exhibits "phase jitter", manifested as cycle-to-cycle variation in flame and vorticity field at the same excitation phase. Phase jitter is shown to be a function of separation point dynamics, downstream convection time, and amplitude of acoustic excitation. It leads to fairly significant differences between instantaneous and ensemble averaged flow fields and, in particular, the decay rate of the vorticity in the axial direction.

show abstract

Flame Driving of Longitudinal Instabilities in Dump Type Ramjet Combustors

Cited by 68 publications

References 6 publications

The role of flow interaction in flame–flame interaction events in a dual burner experiment

The role of flow interaction in flame–flame interaction events in a dual burner experiment

Structure of Flames in Flame Interaction Zones

Vortex Phase-Jitter in Acoustically Excited Bluff Body Flames

Contact Info

Product

Resources

About