Simultaneous two-shot CH planar laser-induced fluorescence and particle image velocimetry measurements in lifted CH4/air diffusion flames

Watson, K.A.; Lyons, Kent; Carter, C.D.; Donbar, Jeffrey M.

doi:10.1016/s1540-7489(02)80231-0

Cited by 44 publications

(28 citation statements)

References 23 publications

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“…These leading edge flames are often present at the stabilization point of lifted spray investigated by a twodimensional laser-sheet imaging technique, as has been described earlier. The nature of the flamefront in the stabilization region of the spray-jet flame is vibrant topic of research [34][35][36], along with the corresponding work in gaseous flames [39][40][41][42][43][44][45][46][47]. Whether all spray flames exhibit "leading edge' flame structures as shown by our group for the gaseous and for some spray cases case is a major question to be addressed by our group in future work.…”

Section: Research Results In Spray Flames At Ncsumentioning

confidence: 84%

Stabilization and Blowout of Gaseous- and Spray-Jet Flames

Lyons¹

2004

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Section: Research Results In Spray Flames At Ncsumentioning

confidence: 84%

Stabilization and Blowout of Gaseous- and Spray-Jet Flames

Lyons¹

2004

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“…A diffusion flame has no burning velocity so it is the premixed flame front that is generally assumed to act as a stabilizing anchor. Many studies, like that of Muñiz and Mungal [1] and Watson et al [2][3][4], have investigated stable lifted flame reaction zone structures that settle at moderate downstream positions. If the reaction zone moves further downstream, it eventually enters a region that can no longer support combustion due to the low fuel concentration and all reaction abruptly ceases, a condition known as flame blowout (Kalghatgi [5], Pitts [6], Coats [7], Chao et al [8,9].…”

Section: Introductionmentioning

confidence: 99%

“…Since the blowout phenomenon happens typically in an abrupt and unpredictable manner, its transient characteristics are difficult to study experimentally. Additionally, the large width of the fuel jet, the small gradients in the scalar and velocity fields, and the relatively low values of fuel concentration make the situation, in many ways, more challenging to fully characterize than the situations described in the studies of Watson et al [2][3][4].…”

Section: Introductionmentioning

confidence: 99%

Observations on Jet-Flame Blowout

Moore

McCraw

Lyons

2008

International Journal of Reacting Systems

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The mechanisms that cause jet-flame blowout, particularly in the presence of air coflow, are not completely understood. This work examines the role of fuel velocity and air coflow in the blowout phenomenon by examining the transient behavior of the reaction zone at blowout. The results of video imaging of a lifted methane-air diffusion flame at near blowout conditions are presented. Two types of experiments are described. In the first investigation, a flame is established and stabilized at a known, predetermined downstream location with a constant coflow velocity, and then the fuel velocity is subsequently increased to cause blowout. In the other , an ignition source is used to maintain flame burning near blowout and the subsequent transient behavior to blowout upon removal of the ignition source is characterized. Data from both types of experiments are collected at various coflow and jet velocities. Images are used to ascertain the changes in the leading edge of the reaction zone prior to flame extinction that help to develop a physically-based model to describe jet-flame blowout. The data report that a consistent predictor of blowout is the prior disappearance of the axially oriented flame branch. This is witnessed despite a turbulent flames' inherent variable behavior. Interpretations are also made in the light of analytical mixture fraction expressions from the literature that support the notion that flame blowout occurs when the leading edge reaches the vicinity of the lean-limit contour, which coincides approximately with the conditions for loss of the axially oriented flame structure.

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“…The time resolution of conventional PLIF measurement is of the order of Hz, which is limited by experimental instruments, in most cases by camera and laser power. Recently, several time resolved PLIF measurement have been reported (Kychakoff et al 1987, Seitzman et al 1994, Schefer et al 1994, Kaminski et al 1999, Nygren et al 2001, Watson et al 2002, Hult et al 2005. To investigate mechanism of flame stabilization of the turbulent jet diffusion flames, double-pulsed CH PLIF and CH 4 Raman scattering technique has been reported by Schefer et al (1994) and simultaneous CH double-pulsed PLIF and particle image velocimetry (PIV) has been conducted by Watson et al (2002).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, several time resolved PLIF measurement have been reported (Kychakoff et al 1987, Seitzman et al 1994, Schefer et al 1994, Kaminski et al 1999, Nygren et al 2001, Watson et al 2002, Hult et al 2005. To investigate mechanism of flame stabilization of the turbulent jet diffusion flames, double-pulsed CH PLIF and CH 4 Raman scattering technique has been reported by Schefer et al (1994) and simultaneous CH double-pulsed PLIF and particle image velocimetry (PIV) has been conducted by Watson et al (2002). By using 4 head YAG laser cluster, Kaminski et al (1999), Nygren et al (2001) and Hult et al (2005) have investigated dynamics of the flame front from time resolved OH PLIF.…”

Section: Introductionmentioning

confidence: 99%

CH double-pulsed PLIF measurement in turbulent premixed flame

et al. 2008

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The flame displacement speeds in turbulent premixed flames have been measured directly by the CH double-pulsed planar laser-induced fluorescence (PLIF). The CH double-pulsed PLIF system consists of two independent conventional CH PLIF measurement systems, and laser beams from each laser system are lead to same optical pass using the difference of polarization. The highly time-resolved measurements are conducted in relatively high Reynolds number turbulent premixed flames on a swirl-stabilized combustor. Since the time interval of the successive CH PLIF can be selected to any optimum value for the purpose intended, both of the large scale dynamics and local displacement of the flame front can be discussed. By selecting an appropriate time interval (100µs~200µs), deformations of the flame front are captured clearly. Successive CH fluorescence images reveal the burning/generating process of the unburned mixtures or the handgrip structures in the burnt gas, which have been predicted by three-dimensional direct numerical simulations of turbulent premixed flames. To evaluate the local flame displacement speed directly from the successive CH images, a flame front identification and displacement vector evaluation schemes are developed. Direct measurements of the flame displacement speed are conducted by selecting a minute time interval (≈30µs) for different Reynolds number (Re λ = 63.1~115.0). Local flame displacement speeds coincide well for different Reynolds number cases, which suggests the correctness of the flamelet concept. Furthermore, comparisons of the mean flame displacement speed and the mean fluid velocity show that the convection in the turbulent flames will affect the flame displacement speed for high Reynolds number flames.

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Simultaneous two-shot CH planar laser-induced fluorescence and particle image velocimetry measurements in lifted CH4/air diffusion flames

Cited by 44 publications

References 23 publications

Stabilization and Blowout of Gaseous- and Spray-Jet Flames

Stabilization and Blowout of Gaseous- and Spray-Jet Flames

Observations on Jet-Flame Blowout

CH double-pulsed PLIF measurement in turbulent premixed flame

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