Chemiluminescent emission measurement of a diffusion flame jet in a loudspeaker induced standing wave

Farhat, S; Ng, W B; Zhang, Y.

doi:10.1016/j.fuel.2005.03.020

Cited by 35 publications

(7 citation statements)

References 5 publications

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“…The knowledge of these visible flame signatures has enabled the development of non-intrusive, line-of-sight measurement techniques for the purpose of combustion diagnostics and control. Earlier, optical diagnostic systems, such as a PMT (photomultiplier tube) [11], were limited to performing global data acquisition of the target emission feature. For this reason, quantitative results often needed to be complemented with qualitative flame illustrations, and hence required an imaging device.…”

Section: Introductionmentioning

confidence: 99%

Dynamic application of digital image and colour processing in characterizing flame radiation features

Huang

Zhang

2010

Meas. Sci. Technol.

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In this work, the experimental investigation of the dynamic flame properties of flame flickering and equivalence ratio sensing of a combustion process was done. In particular, the time-varied flame properties were examined using a novel digital image and colour processing methodology. This technique makes use of the observed correlation between a digital image colour signal and physical flame radiation characteristics in the visible wavelength domain. Aspects of RGB and HSV colour modelling principles were applied to show that the addition of colour identification in the image processing of high-speed flame image data could yield three useful parameters which are related to the dynamic behaviour of different flame emanating components. First, the validity of the colour identities for tracking the yellowish-red diffusion and greenish-blue premixed flame colourations were examined by comparing their respective flickering frequency profiles. Then, the usefulness of the extracted Rdiffusion, Gpremixed and Bpremixed colour signals to abstractly represent the behaviour of soot, C2* and CH* emission characteristics in a dynamic flame transition from diffusion to stoichiometric premixed condition was demonstrated. In particular, the colour signal ratio Bpremixed/Gpremixed was correlated to exemplify the approximate time-varied state of the equivalence ratio from the imaged combustion phenomenon.

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Section: Introductionmentioning

confidence: 99%

Dynamic application of digital image and colour processing in characterizing flame radiation features

Huang

Zhang

2010

Meas. Sci. Technol.

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“…The flame pinch off was observed with the strong low frequency perturbations and the flame exhibits a low-pass filter characteristic. The dynamics of the jet diffusion flame in a standing wave have been studied [32][33][34][35][36]. The low-pass characteristic of the response of the jet diffusion flame have also been observed in this geometry.…”

Section: Introductionmentioning

confidence: 95%

Characterizations of the Non-linear Responses of a Non-premixed Flame to the Low Frequency Acoustic Excitations

Pan¹,

Ji²,

Zhu³

2023

Preprint

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The heat release response of the flame to acoustic excitation is a critical factor for understanding combustion instability. In the present work, the nonlinear heat release response of a methane-air non-premixed flame to the low frequency acoustic excitations is experimentally investigated. The flame describing function (FDF) was measured based on the overall CH* chemiluminescence intensity and the velocity fluctuations obtained by two-microphone method. The CH* chemiluminescence images and the schlieren images were analyzed to reveal the mechanism of nonlinear response. The excitation frequency ranges from 10Hz to 120Hz. The forced relative velocity fluctuation amplitude ranges from 0.10 to 0.50. The corresponding flame Strouhal number (Stf) ranges from 0.43 to 4.67. The study has shown that the flame length responds more sensitively to changes in excitation amplitude when subjected to relatively high frequency excitations. The normalized flame length (Lf/D) decreases from 3.79 to 2.37 with the increase of excitation amplitude at excitation frequency of 100Hz. The number of oscillation zones along the flame increases with increasing excitation frequency, which is consistent with the increase of the Stf. The low-pass filtering characteristic of FDF is caused by the dispersion of multiple oscillation zones, as well as the cancellation effect of the adjacent oscillation zones under relatively high frequency excitation. The cancellation effect of the positive and negative oscillation zones with various Stf is main mechanism for the local gain peak and valley. When two adjacent oscillation regions have approximate amplitudes, the overall phase-lag becomes more sensitive to changes in excitation frequency and amplitude. This sensitivity leads to nonlinear anomalous changes in the phase-lag near the frequency corresponding to the gain valley. The calculated disturbance convection time is consistent with the measured time delay in the short flame scenario. Future research is necessary to establish whether the observed agreement occurs due to the oscillation zone consistently occurring proximate to the flame's center of mass, coupled with a precise determination of the average convective velocity.

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“…Recent studies on premixed conical flames (Karimi et al, 2009;Gotoda et al, 2011;Kim and Hochgreb, 2012;Kashinath et al, 2014;Domen et al, 2015) and premixed V-flames (Dowling, 1999;Vishnu et al, 2015) have indicated the presence of several interesting dynamic characteristics such as quasiperiodicity, frequency locking, and chaos, apart from limit cycles. However, since many practical applications use non-premixed or partially premixed flames, dynamic characterization of the thermoacoustic characteristics of such flames was also performed by various researchers (Farhat et al, 2005;Tyagi et al, 2007;Balasubramanian and Sujith, 2008;Chen et al, 2012Chen et al, , 2013Illingworth et al, 2013;Magina et al, 2013;Mondal et al, 2014;Magina and Lieuwen, 2014;Magina et al, 2015;Pawar et al, 2016;Magina and Lieuwen, 2016;Magina et al, 2017) revealing striking differences with premixed flames.…”

Section: Introductionmentioning

confidence: 99%

Dynamic Characterization of a Ducted Inverse Diffusion Flame Using Recurrence Analysis

Sen

Gangopadhyay

Bhattacharya

et al. 2017

Combustion Science and Technology

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Normal diffusion flame or partially premixed flame is used in many applications such as aviation engines, tanks, ocean vessels, and industrial furnaces because of its high flame stability and relatively low susceptibility to dynamic instabilities compared to lean premixed flames, which give lower emissions. However, associated with such flames are high NO x and soot emissions, which are particularly high for heavier hydrocarbon fuels.Increasingly stringent environmental norms have thus dictated the search for alternate approaches; one such being the inverse diffusion flame, which is currently being used in rocket motors, for staged combustion in gas turbine combustors, and furnaces. However, the dynamic response of such a flame, particularly in ducted applications where a coupling between unsteady heat release rate and duct acoustics may occur, is relatively less explored.The present work aims to plug that knowledge gap through an experimental investigation of a laboratory-scale ducted inverse diffusion flame. Two parametric variations of the flame were performed -variation of the flame position and variation of the air flow rate. Using tools of nonlinear dynamics such as phase space reconstruction and recurrence quantification, several interesting dynamic characteristics were observed such as limit cycles, intermittency, and homoclinic orbits. For a constant air flow rate, the system was observed to transition from a type-II intermittency regime to a limit cycle and then again to intermittent behavior as the position of the flame within the duct was varied. A similar trend was observed when the air flow rate was varied at a fixed flame position.

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Chemiluminescent emission measurement of a diffusion flame jet in a loudspeaker induced standing wave

Cited by 35 publications

References 5 publications

Dynamic application of digital image and colour processing in characterizing flame radiation features

Dynamic application of digital image and colour processing in characterizing flame radiation features

Characterizations of the Non-linear Responses of a Non-premixed Flame to the Low Frequency Acoustic Excitations

Dynamic Characterization of a Ducted Inverse Diffusion Flame Using Recurrence Analysis

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