- Email: [email protected]
Time-dependent measurements of flame temperature and the OH radical in the unsteady extinction of non-premixed flames
Combustion and Flame 141 (2005) 186–190 www.elsevier.com/locate/combustflame
Brief Communication
Time-dependent measurements of flame temperature and the OH radical in the unsteady extinction of non-premixed flames Uen Do Lee a , Kwang Chul Oh a , Hyun Dong Shin a,∗ , Ki Ho Lee b a Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong,
Yuseong-gu, Daejon, 305-701, Republic of Korea b Research and Development Division for Hyundai Motor Company, 772-1, Jangduk-Dong, Whasung-Si, Gyunggi-Do,
Republic of Korea Received 24 May 2004; received in revised form 5 January 2005; accepted 7 January 2005
Abstract The extinction point, time-dependent flame temperature, relative [OH], and the instantaneous luminosity of a flame during the unsteady extinction process were measured in non-premixed counterflow flames, and characteristics of each parameter near the extinction limit were investigated. We found that the unsteady extinction point is much higher than the steady extinction point and OH radical is a more adequate indicator of extinction than temperature, especially for turbulent and unsteady flames. 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
1. Introduction Flame extinction and ignition are unsteady processes. Though extinction is an inherently transient process, steady and quasi-steady approaches have been used to gain an understanding of flame extinction, and these results have been applied to the modeling of turbulent combustion [1–7]. In steady flames, an extinction point can be distinctly defined and various parameters have been used as a criterion for extinction. Thus, Konnov et al. [8] measured flame temperature and [OH] in steady flames with various boundary conditions, and suggested that the OH radical is a reliable indicator of extinction. Re* Corresponding author. Fax: +82-42-869-8820.
E-mail address: [email protected] (H.D. Shin).
cently, various attempts have been made to understand unsteady flames by using extinction and turbulent flames [9–18]. Representative parameters for describing a flame, such as temperature [9,10], concentrations of important radicals [11–17], and chemiluminescence [18], have been used as criteria of flame extinction. Although unsteady values of various parameters have been reported, definition of the extinction point of an unsteady flame and determination of which parameter is the most appropriate indicator of extinction remain challenging problems. In this study, the extinction of an opposed-jet flame, a time-dependent flame temperature, relative [OH], and the instantaneous luminosity of a flame during the unsteady extinction process were measured, and the characteristics of each parameter near the extinction limit were investigated.
0010-2180/$ – see front matter 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.combustflame.2005.01.001
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
187
Fig. 1. Experimental setup.
2. Experimental methods Fig. 1 illustrates the experimental setup, which consists of three parts: a combustor, a piston assembly, and an optical measurement system. The combustor is based on an opposed-jet, non-premixed burner. The main nozzle has an internal diameter of 14 mm, that of the coflow nozzle is 20 mm, and the distance between the air and fuel nozzles is 14 mm. A quartz window for a laser beam is placed on the rear side of each burner for optical measurements. Diluted fuel (CH4 + N2 ) is supplied to the right-hand main nozzle and dried air to the left and the same amount of N2 to each coflow nozzle. The piston assembly, composed of three pistons, is used to introduce changes in the velocities of the gas flows. The lower piston is an actuator, and two upper pistons provide an equal velocity change for the air and fuel streams. The instantaneous velocity change at the nozzle exit is measured by hot-wire anemometry (Dantec CTA 56C17). Two kinds of laser diagnostics are used to examine the time-dependent flame temperature and also [OH] by laser-induced fluorescence (LIF). To measure flame temperature, a second harmonic Nd:YAG laser (Continuum 500 mJ, 532 nm) for Rayleigh scattering and an ICCD camera (Princeton Inc. 512 × 512) with a bandpass filter (532 nm, FWHM 10 nm) are used. [OH] is measured by LIF using a Nd:YAG pumped
dye laser tuned to 283.01 nm to excite the Q1 6 line of the A2 Σ + ← X 2 Π (v = 1, v = 0) transition in the saturation regime [20]. An ICCD camera with UG-11 and WG-305 filters was used. The transient chemiluminescence of the flame was photographed with a high-speed ICCD (HICCD) camera (Phantom V7.0). The laser system, the cameras, and the hotwire anemometry were all synchronized with piston movement by means of a pulse delay generator.
3. Results and discussion Fig. 2 illustrates the transient evolution of chemiluminescence images of the CH radical. The unsteady velocity change starts to perturb the flame at t = 1 ms and local quenching occurs after t = 7 ms. Quenching begins in the middle of the flame’s surface; as time passes, the quenching area evolves toward the axis, and, subsequently, the flame in the central region is eventually extinguished. The far outer region of the flame is of no concern in this study. It is noted that extinction starts from the outer edges and progresses inward; this results from the distribution of local strain rates in a radial direction in an opposed jet [18,19]. We define the unsteady extinction point as the time at which the flame of the central region disappears; i.e., the eventual extinction of the flame in
188
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
Fig. 2. Chemiluminescence images of the flame during extinction: (a) 90◦ view, (b) 45◦ view (taken with a HICCD camera, 2000 fps). [CH4 ]:[N2 ] = 5:5, ainitial = 266.2 s−1 .
Fig. 3. (a) Rayleigh scattering signal without flame and flame chemiluminescence. (b) Signal index. (c) Rayleigh scattering and OH LIF images during the unsteady extinction process. [CH4 ]:[N2 ] = 5:5, ainitial = 226.8 s−1 .
Fig. 2 occurs at t = 15 ms. As such, we measure unsteady extinction points for different dilutions of the fuel, and the unsteady extinction limit is much larger than the steady extinction limit [9,10,13,14]. Fig. 3a shows the Rayleigh scattering signal without a flame. The Rayleigh scattering signal from the fuel side is much larger than that from the air side, because the Rayleigh cross section of CH4 is larger than that of air. Fig. 3c illustrates evolution of one-dimensional time-dependent Rayleigh scattering and OH LIF signals during the unsteady extinction process. The Rayleigh scattering images reveal a decrease in thermal thickness over time, and the OH
LIF demonstrate that the concentration and change in the distribution of OH radicals. The maximum flame temperature (Tmax ) was calculated by comparing the Rayleigh scattering signals of the ambient air (Rair, 298 K ) and flame (Rflame ) [21] using (Rair, 298 K − Rbackground noise ) Tflame = Tair (Rflame − Rbackground noise ) n xi σRi flame . × i m i xi σRi air
(1)
To calculate the mixture-averaged Rayleigh cross sections ( ni xi σRi ) in the region of maximum temperature, we consider the Rayleigh cross sections
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
189
Fig. 4. Behavior of maximum flame temperature with respect to strain rate history. ainitial = 226.8 s−1 .
Fig. 5. Change in the maximum relative OH intensity with respect to the strain rate history. ainitial = 226.8 s−1 .
(σRi ) of eight species (H2 , O2 , OH, CO, CO2 , H2 O, N2 , CH4 ) [21]; the mole fractions of species (xi ) at Tmax are obtained from a numerical simulation performed with the OFFDIF code of Chemkin III [23], using GRI-3.0 [24]. In this case (λ = 532 nm, [CH4 ]:[N2 ] = 5:5), ( ni xi σRi )flame varies from 6.339 × 1028 to 6.312 × 1028 cm2 , as the strain rate changes from an initial value (ainitial ) of 226.8 s−1 to a steady extinction (aE, steady ) of 354.4 s−1 . The effect of varying in the Rayleigh cross section on the estimated value of Tmax is less than 8 K over the entire experimental range. We used 10 single-shot images to measure the Rayleigh scattering and the OH LIF signal at each time step.
Fig. 4 shows the change in strain rate, the steady and unsteady extinction points, and the time-dependent Tmax for different dilutions of the fuel. The strain rate is calculated [5] using a=
2(−Voxidant ) L ρfuel 1/2 Vfuel × 1+ . (−Voxidant ) ρoxidant
(2)
L is the distance between the fuel and air nozzles. The strain rate increases linearly over time, and extinction occurs at t = 14 ms and t = 19.4 ms, for [CH4 ]:[N2 ] = 4:6 and [CH4 ]:[N2 ] = 5:5, respec-
190
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
tively. Each unsteady extinction point is measured using chemiluminescence images taken with the HICCD camera and is much larger than the steady extinction point. The change in Tmax in Fig. 4 shows the upper branch of the well-known S-shaped curve [22] of the unsteady extinction process. The value of Tmax is nearly constant in the starting region of the velocity change; it then decreases gradually with increasing strain rate, and finally decreases rapidly near the extinction limit. The nearly constant Tmax in the starting region results from the delay of the convectivediffusive zone in the unsteady flow field [9,13]. The lower bound of Tmax , where the flame maintains its luminosity (1 ms before the extinction point), is ≈1600 K. The maximum relative OH intensity with respect to time is shown in Fig. 5. The maximum OH intensities of each time step were normalized by a maximum OH intensity of t = 0. The plots of [OH] and flame temperature illustrate similar trends in the starting region of the velocity change, i.e., the relative [OH] is nearly constant when t 4 ms and t 8 ms for [CH4 ]:[N2 ] = 4:6 and [CH4 ]:[N2 ] = 5:5, respectively. It is remarkable that the relative OH intensity near the extinction limit (t = 13 or 19 ms) decreases to 70% of the initial value and [OH] rapidly decreases below Tmax = 1600 K. In Fig. 4, near the extinction limits, the time elapsed for Tmax to decrease to the ambient temperature is 3–4 ms, i.e., comparable to the characteristic time of the flow (i.e., 1/strain rate). The OH radical also has the residence time shown in Fig. 5, but it is very short and less than 1 ms. These results imply that in contrast to the OH radical, the flame temperature depends on any unsteadiness in the flow near the extinction limit. Consequently, it can be confirmed that the OH radical is a more adequate indicator of extinction phenomena than temperature, especially for turbulent and unsteady flames.
Acknowledgment This research was supported by the Korea Science and Technology Foundation (KOSEF) through the Combustion Engineering Research Center (CERC).
References [1] H. Tsuji, Prog. Energy Combust. Sci. 8 (1982) 93–119.
[2] F.A. Williams, Prog. Energy Combust. Sci. 26 (2000) 657–682. [3] I.K. Puri, K. Seshadri, Combust. Flame 65 (1986) 137– 150. [4] G. Dixon-Lewis, M. Massaghi, Proc. Combust. Inst. 22 (1988) 1461–1470. [5] H.K. Chelliah, C.K. Law, T. Ueda, M.D. Smook, F.A. Williams, Proc. Combust. Inst. 23 (1990) 503–511. [6] J. Du, R.L. Azelbaum, Proc. Combust. Inst. 26 (1996) 1137–1142. [7] N. Peters, Prog. Energy Combust. Sci. 10 (1984) 319– 339. [8] A.A. Konnov, M. Idir, J.L. Delafau, C. Vovelle, Combust. Flame 105 (1996) 308–320. [9] V.R. Katta, T.R. Meyer, M.S. Brown, J.R. Gord, W.M. Roquemore, Combust. Flame 137 (2004) 198–221. [10] E.J. Lee, K.H. Oh, H.D. Shin, Proc. Combust. Inst. 28 (2000) 2079–2084. [11] T.M. Brown, R.W. Pitz, C.J. Sung, Proc. Combust. Inst. 27 (1998) 703–710. [12] D. Thevenin, P.H. Renard, J.C. Rolon, S. Candle, Proc. Combust. Inst. 27 (1998) 719–726. [13] V.S. Santoro, D.C. Kyritsis, A. Linan, A. Gomez, Proc. Combust. Inst. 28 (2000) 2109–2116. [14] D.C. Kyritsis, V.S. Santoro, A. Gomez, Proc. Combust. Inst. 29 (2002) 1679–1685. [15] K.A. Watson, K.M. Lyons, J.M. Donbar, C.D. Carter, Combust. Flame 117 (1999) 257–271. [16] D. Han, M.G. Mungal, Combust. Flame 132 (2003) 565–590. [17] J.M. Donbar, J.F. Driscoll, C.D. Carter, Combust. Flame 125 (2001) 1239–1257. [18] E. Korusoy, J.H. Whitelaw, Exp. Fluids 33 (2002) 75– 89. [19] J.C. Rolon, D. Veynante, J.P. Martin, F. Durst, Exp. Fluids 11 (1991) 313–324. [20] J.T. Salmon, N.M. Laurendeau, Appl. Opt. 24 (1985) 65. [21] I. Namer, R.W. Schefer, Exp. Fluids 3 (1985) 1–9. [22] G. Dixon-Lewis, Proc. Combust. Inst. 23 (1990) 305– 324. [23] R.J. Kee, F.M. Rupley, J.A. Miller, M.E. Coltrin, J.F. Grcar, E. Meeks, H.K. Moffat, A.E. Lutz, G. DixonLewis, M.D. Smooke, J. Warnatz, G.H. Evans, R.S. Larson, R.E. Mitchell, L.R. Petzold, W.C. Reynolds, M. Caracotsios, W.E. Stewart, P. Glarborg, C. Wang, O. Adigun, CHEMKIN Collection, Release 3.6, Reaction Design, Inc., San Diego, CA, 2000. [24] G.P. Smith, D.M. Golden, M. Frenklach, N.W. Moriarty, B. Eiteneer, M. Goldenberg, C.T. Bowman, R.K. Hanson Soonho Song, W.C. Gardiner Jr., V.V. Lissianski, Z. Qin, GRI-Mech 3.0, http://www.me.berkeley. edu/gri_mech/, 2000.
Brief Communication
Time-dependent measurements of flame temperature and the OH radical in the unsteady extinction of non-premixed flames Uen Do Lee a , Kwang Chul Oh a , Hyun Dong Shin a,∗ , Ki Ho Lee b a Department of Mechanical Engineering, Korea Advanced Institute of Science and Technology, 373-1, Guseong-dong,
Yuseong-gu, Daejon, 305-701, Republic of Korea b Research and Development Division for Hyundai Motor Company, 772-1, Jangduk-Dong, Whasung-Si, Gyunggi-Do,
Republic of Korea Received 24 May 2004; received in revised form 5 January 2005; accepted 7 January 2005
Abstract The extinction point, time-dependent flame temperature, relative [OH], and the instantaneous luminosity of a flame during the unsteady extinction process were measured in non-premixed counterflow flames, and characteristics of each parameter near the extinction limit were investigated. We found that the unsteady extinction point is much higher than the steady extinction point and OH radical is a more adequate indicator of extinction than temperature, especially for turbulent and unsteady flames. 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved.
1. Introduction Flame extinction and ignition are unsteady processes. Though extinction is an inherently transient process, steady and quasi-steady approaches have been used to gain an understanding of flame extinction, and these results have been applied to the modeling of turbulent combustion [1–7]. In steady flames, an extinction point can be distinctly defined and various parameters have been used as a criterion for extinction. Thus, Konnov et al. [8] measured flame temperature and [OH] in steady flames with various boundary conditions, and suggested that the OH radical is a reliable indicator of extinction. Re* Corresponding author. Fax: +82-42-869-8820.
E-mail address: [email protected] (H.D. Shin).
cently, various attempts have been made to understand unsteady flames by using extinction and turbulent flames [9–18]. Representative parameters for describing a flame, such as temperature [9,10], concentrations of important radicals [11–17], and chemiluminescence [18], have been used as criteria of flame extinction. Although unsteady values of various parameters have been reported, definition of the extinction point of an unsteady flame and determination of which parameter is the most appropriate indicator of extinction remain challenging problems. In this study, the extinction of an opposed-jet flame, a time-dependent flame temperature, relative [OH], and the instantaneous luminosity of a flame during the unsteady extinction process were measured, and the characteristics of each parameter near the extinction limit were investigated.
0010-2180/$ – see front matter 2005 The Combustion Institute. Published by Elsevier Inc. All rights reserved. doi:10.1016/j.combustflame.2005.01.001
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
187
Fig. 1. Experimental setup.
2. Experimental methods Fig. 1 illustrates the experimental setup, which consists of three parts: a combustor, a piston assembly, and an optical measurement system. The combustor is based on an opposed-jet, non-premixed burner. The main nozzle has an internal diameter of 14 mm, that of the coflow nozzle is 20 mm, and the distance between the air and fuel nozzles is 14 mm. A quartz window for a laser beam is placed on the rear side of each burner for optical measurements. Diluted fuel (CH4 + N2 ) is supplied to the right-hand main nozzle and dried air to the left and the same amount of N2 to each coflow nozzle. The piston assembly, composed of three pistons, is used to introduce changes in the velocities of the gas flows. The lower piston is an actuator, and two upper pistons provide an equal velocity change for the air and fuel streams. The instantaneous velocity change at the nozzle exit is measured by hot-wire anemometry (Dantec CTA 56C17). Two kinds of laser diagnostics are used to examine the time-dependent flame temperature and also [OH] by laser-induced fluorescence (LIF). To measure flame temperature, a second harmonic Nd:YAG laser (Continuum 500 mJ, 532 nm) for Rayleigh scattering and an ICCD camera (Princeton Inc. 512 × 512) with a bandpass filter (532 nm, FWHM 10 nm) are used. [OH] is measured by LIF using a Nd:YAG pumped
dye laser tuned to 283.01 nm to excite the Q1 6 line of the A2 Σ + ← X 2 Π (v = 1, v = 0) transition in the saturation regime [20]. An ICCD camera with UG-11 and WG-305 filters was used. The transient chemiluminescence of the flame was photographed with a high-speed ICCD (HICCD) camera (Phantom V7.0). The laser system, the cameras, and the hotwire anemometry were all synchronized with piston movement by means of a pulse delay generator.
3. Results and discussion Fig. 2 illustrates the transient evolution of chemiluminescence images of the CH radical. The unsteady velocity change starts to perturb the flame at t = 1 ms and local quenching occurs after t = 7 ms. Quenching begins in the middle of the flame’s surface; as time passes, the quenching area evolves toward the axis, and, subsequently, the flame in the central region is eventually extinguished. The far outer region of the flame is of no concern in this study. It is noted that extinction starts from the outer edges and progresses inward; this results from the distribution of local strain rates in a radial direction in an opposed jet [18,19]. We define the unsteady extinction point as the time at which the flame of the central region disappears; i.e., the eventual extinction of the flame in
188
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
Fig. 2. Chemiluminescence images of the flame during extinction: (a) 90◦ view, (b) 45◦ view (taken with a HICCD camera, 2000 fps). [CH4 ]:[N2 ] = 5:5, ainitial = 266.2 s−1 .
Fig. 3. (a) Rayleigh scattering signal without flame and flame chemiluminescence. (b) Signal index. (c) Rayleigh scattering and OH LIF images during the unsteady extinction process. [CH4 ]:[N2 ] = 5:5, ainitial = 226.8 s−1 .
Fig. 2 occurs at t = 15 ms. As such, we measure unsteady extinction points for different dilutions of the fuel, and the unsteady extinction limit is much larger than the steady extinction limit [9,10,13,14]. Fig. 3a shows the Rayleigh scattering signal without a flame. The Rayleigh scattering signal from the fuel side is much larger than that from the air side, because the Rayleigh cross section of CH4 is larger than that of air. Fig. 3c illustrates evolution of one-dimensional time-dependent Rayleigh scattering and OH LIF signals during the unsteady extinction process. The Rayleigh scattering images reveal a decrease in thermal thickness over time, and the OH
LIF demonstrate that the concentration and change in the distribution of OH radicals. The maximum flame temperature (Tmax ) was calculated by comparing the Rayleigh scattering signals of the ambient air (Rair, 298 K ) and flame (Rflame ) [21] using (Rair, 298 K − Rbackground noise ) Tflame = Tair (Rflame − Rbackground noise ) n xi σRi flame . × i m i xi σRi air
(1)
To calculate the mixture-averaged Rayleigh cross sections ( ni xi σRi ) in the region of maximum temperature, we consider the Rayleigh cross sections
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
189
Fig. 4. Behavior of maximum flame temperature with respect to strain rate history. ainitial = 226.8 s−1 .
Fig. 5. Change in the maximum relative OH intensity with respect to the strain rate history. ainitial = 226.8 s−1 .
(σRi ) of eight species (H2 , O2 , OH, CO, CO2 , H2 O, N2 , CH4 ) [21]; the mole fractions of species (xi ) at Tmax are obtained from a numerical simulation performed with the OFFDIF code of Chemkin III [23], using GRI-3.0 [24]. In this case (λ = 532 nm, [CH4 ]:[N2 ] = 5:5), ( ni xi σRi )flame varies from 6.339 × 1028 to 6.312 × 1028 cm2 , as the strain rate changes from an initial value (ainitial ) of 226.8 s−1 to a steady extinction (aE, steady ) of 354.4 s−1 . The effect of varying in the Rayleigh cross section on the estimated value of Tmax is less than 8 K over the entire experimental range. We used 10 single-shot images to measure the Rayleigh scattering and the OH LIF signal at each time step.
Fig. 4 shows the change in strain rate, the steady and unsteady extinction points, and the time-dependent Tmax for different dilutions of the fuel. The strain rate is calculated [5] using a=
2(−Voxidant ) L ρfuel 1/2 Vfuel × 1+ . (−Voxidant ) ρoxidant
(2)
L is the distance between the fuel and air nozzles. The strain rate increases linearly over time, and extinction occurs at t = 14 ms and t = 19.4 ms, for [CH4 ]:[N2 ] = 4:6 and [CH4 ]:[N2 ] = 5:5, respec-
190
U.D. Lee et al. / Combustion and Flame 141 (2005) 186–190
tively. Each unsteady extinction point is measured using chemiluminescence images taken with the HICCD camera and is much larger than the steady extinction point. The change in Tmax in Fig. 4 shows the upper branch of the well-known S-shaped curve [22] of the unsteady extinction process. The value of Tmax is nearly constant in the starting region of the velocity change; it then decreases gradually with increasing strain rate, and finally decreases rapidly near the extinction limit. The nearly constant Tmax in the starting region results from the delay of the convectivediffusive zone in the unsteady flow field [9,13]. The lower bound of Tmax , where the flame maintains its luminosity (1 ms before the extinction point), is ≈1600 K. The maximum relative OH intensity with respect to time is shown in Fig. 5. The maximum OH intensities of each time step were normalized by a maximum OH intensity of t = 0. The plots of [OH] and flame temperature illustrate similar trends in the starting region of the velocity change, i.e., the relative [OH] is nearly constant when t 4 ms and t 8 ms for [CH4 ]:[N2 ] = 4:6 and [CH4 ]:[N2 ] = 5:5, respectively. It is remarkable that the relative OH intensity near the extinction limit (t = 13 or 19 ms) decreases to 70% of the initial value and [OH] rapidly decreases below Tmax = 1600 K. In Fig. 4, near the extinction limits, the time elapsed for Tmax to decrease to the ambient temperature is 3–4 ms, i.e., comparable to the characteristic time of the flow (i.e., 1/strain rate). The OH radical also has the residence time shown in Fig. 5, but it is very short and less than 1 ms. These results imply that in contrast to the OH radical, the flame temperature depends on any unsteadiness in the flow near the extinction limit. Consequently, it can be confirmed that the OH radical is a more adequate indicator of extinction phenomena than temperature, especially for turbulent and unsteady flames.
Acknowledgment This research was supported by the Korea Science and Technology Foundation (KOSEF) through the Combustion Engineering Research Center (CERC).
References [1] H. Tsuji, Prog. Energy Combust. Sci. 8 (1982) 93–119.
[2] F.A. Williams, Prog. Energy Combust. Sci. 26 (2000) 657–682. [3] I.K. Puri, K. Seshadri, Combust. Flame 65 (1986) 137– 150. [4] G. Dixon-Lewis, M. Massaghi, Proc. Combust. Inst. 22 (1988) 1461–1470. [5] H.K. Chelliah, C.K. Law, T. Ueda, M.D. Smook, F.A. Williams, Proc. Combust. Inst. 23 (1990) 503–511. [6] J. Du, R.L. Azelbaum, Proc. Combust. Inst. 26 (1996) 1137–1142. [7] N. Peters, Prog. Energy Combust. Sci. 10 (1984) 319– 339. [8] A.A. Konnov, M. Idir, J.L. Delafau, C. Vovelle, Combust. Flame 105 (1996) 308–320. [9] V.R. Katta, T.R. Meyer, M.S. Brown, J.R. Gord, W.M. Roquemore, Combust. Flame 137 (2004) 198–221. [10] E.J. Lee, K.H. Oh, H.D. Shin, Proc. Combust. Inst. 28 (2000) 2079–2084. [11] T.M. Brown, R.W. Pitz, C.J. Sung, Proc. Combust. Inst. 27 (1998) 703–710. [12] D. Thevenin, P.H. Renard, J.C. Rolon, S. Candle, Proc. Combust. Inst. 27 (1998) 719–726. [13] V.S. Santoro, D.C. Kyritsis, A. Linan, A. Gomez, Proc. Combust. Inst. 28 (2000) 2109–2116. [14] D.C. Kyritsis, V.S. Santoro, A. Gomez, Proc. Combust. Inst. 29 (2002) 1679–1685. [15] K.A. Watson, K.M. Lyons, J.M. Donbar, C.D. Carter, Combust. Flame 117 (1999) 257–271. [16] D. Han, M.G. Mungal, Combust. Flame 132 (2003) 565–590. [17] J.M. Donbar, J.F. Driscoll, C.D. Carter, Combust. Flame 125 (2001) 1239–1257. [18] E. Korusoy, J.H. Whitelaw, Exp. Fluids 33 (2002) 75– 89. [19] J.C. Rolon, D. Veynante, J.P. Martin, F. Durst, Exp. Fluids 11 (1991) 313–324. [20] J.T. Salmon, N.M. Laurendeau, Appl. Opt. 24 (1985) 65. [21] I. Namer, R.W. Schefer, Exp. Fluids 3 (1985) 1–9. [22] G. Dixon-Lewis, Proc. Combust. Inst. 23 (1990) 305– 324. [23] R.J. Kee, F.M. Rupley, J.A. Miller, M.E. Coltrin, J.F. Grcar, E. Meeks, H.K. Moffat, A.E. Lutz, G. DixonLewis, M.D. Smooke, J. Warnatz, G.H. Evans, R.S. Larson, R.E. Mitchell, L.R. Petzold, W.C. Reynolds, M. Caracotsios, W.E. Stewart, P. Glarborg, C. Wang, O. Adigun, CHEMKIN Collection, Release 3.6, Reaction Design, Inc., San Diego, CA, 2000. [24] G.P. Smith, D.M. Golden, M. Frenklach, N.W. Moriarty, B. Eiteneer, M. Goldenberg, C.T. Bowman, R.K. Hanson Soonho Song, W.C. Gardiner Jr., V.V. Lissianski, Z. Qin, GRI-Mech 3.0, http://www.me.berkeley. edu/gri_mech/, 2000.