OSA's Digital Library

Optics Express

Optics Express

  • Editor: Andrew M. Weiner
  • Vol. 22, Iss. 3 — Feb. 10, 2014
  • pp: 3447–3457
« Show journal navigation

Laser induced spark ignition of coaxial methane/oxygen/nitrogen diffusion flames

Xiaohui Li, Yang Yu, Xin Yu, Chang Liu, Rongwei Fan, and Deying Chen  »View Author Affiliations


Optics Express, Vol. 22, Issue 3, pp. 3447-3457 (2014)
http://dx.doi.org/10.1364/OE.22.003447


View Full Text Article

Acrobat PDF (1085 KB)





Browse Journals / Lookup Meetings

Browse by Journal and Year


   


Lookup Conference Papers

Close Browse Journals / Lookup Meetings

Article Tools

Share
Citations

Abstract

We report the laser induced spark ignition (LSI) of coaxial methane/oxygen/nitrogen diffusion flames using the 1064 nm output of a Q-switched Nd:YAG laser. The minimum ignition energy (MIE) and ignition time of the LSI has been determined by measuring the emission signals due to the ignited flames. The effects of the gas mixture properties, including the overall equivalence ratio (Ф), oxygen concentration and flow rate, and the ignition positions on the two parameters have been investigated systematically. The variation of the MIE and ignition time with the experimental conditions has been compared with the existing results and discussed with a special concentration on the effects of the local Ф.

© 2014 Optical Society of America

1. Introduction

During the last two decades, laser induced spark ignition (LSI) has been proposed as a promising ignition technique [1

1. P. D. Ronney, “Laser versus conventional ignition of flames,” Opt. Eng. 33(2), 510–521 (1994). [CrossRef]

13

13. M. Lackner, S. Charareh, F. Winter, K. Iskra, D. Rüdisser, T. Neger, H. Kopecek, and E. Wintner, “Investigation of the early stages in laser-induced ignition by Schlieren photography and laser-induced fluorescence spectroscopy,” Opt. Express 12(19), 4546–4557 (2004). [CrossRef] [PubMed]

] with many potential benefits, including easier control of ignition position and ignition timing, no electrodes and thus no heat loss towards the combustion chamber that may lead to extinguishment of the combustion systems [5

5. M. Weinrotter, H. Kopecek, E. Wintner, M. Lackner, and F. Winter, “Application of laser ignition to hydrogen-air mixtures at high pressures,” Int. J. Hydrogen Energy 30(3), 319–326 (2005). [CrossRef]

], wider ignitable equivalence ratio range [11

11. G. Herdin, J. Klausner, E. Wintner, M. Weinrotter, J. Graf, and K. Iskra, “Laser ignition - a new concept to use and increase the pontentials of gas engines,” in ASME Internal Combustion Engine Division 2005 Fall Technical Conference:AERS-ARICE Symposium on Gas Fired Reciprocating Engines(Ottawa, Canada, 2005).

], feasibility of multi-point ignition [9

9. M. H. Morsy and S. H. Chung, “Laser-induced multi-point ignition with a single-shot laser using two conical cavities for hydrogen/air mixture,” Exp. Therm. Fluid Sci. 27(4), 491–497 (2003). [CrossRef]

] and ease of synchronization with the diagnostic systems [7

7. J. L. Beduneau, N. Kawahara, T. Nakayama, E. Tomita, and Y. Ikeda, “Laser-induced radical generation and evolution to a self-sustaining flame,” Combust. Flame 156(3), 642–656 (2009). [CrossRef]

]. With the developments of compact and stable solid laser systems [14

14. N. Pavel, M. Tsunekane, and T. Taira, “Composite, all-ceramics, high-peak power Nd:YAG/Cr4+:YAG monolithic micro-laser with multiple-beam output for engine ignition,” Opt. Express 19(10), 9378–9384 (2011). [CrossRef] [PubMed]

] for LSI, practical applications of LSI have been demonstrated in several combustion systems, including internal combustion engines [15

15. G. Liedl, D. Schuocker, B. Geringer, J. Graf, D. Klawatsch, H. P. Lenz, W. F. Piock, M. Jetzinger, and P. Kapus, “Laser induced ignition of gasoline direct injection engines,” Proc. SPIE 5777, 955–959 (2004).

], natural gas engines [11

11. G. Herdin, J. Klausner, E. Wintner, M. Weinrotter, J. Graf, and K. Iskra, “Laser ignition - a new concept to use and increase the pontentials of gas engines,” in ASME Internal Combustion Engine Division 2005 Fall Technical Conference:AERS-ARICE Symposium on Gas Fired Reciprocating Engines(Ottawa, Canada, 2005).

], model scramjet engine [16

16. S. Brieschenk, S. O’Byrne, and H. Kleine, “Laser-induced plasma ignition studies in a model scramjet engine,” Combust. Flame 160(1), 145–148 (2013). [CrossRef]

], and rocket engines [17

17. R. J. Osborne, J. A. Wehrmeyer, H. P. Trinh, and J. W. Early, “Evaluation and characterization study of dual pulse laser-induced spark(DPLIS) for rocket engine ignition system application,” in 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit(AIAA Huntsville, Alabama, 2003), paper 2003–4905. [CrossRef]

24

24. V. Schmidt, U. Wepler, O. Haidn, and M. Oschwald, “Characterization of the primary ignition process of a coaxial GH2/LOx spray,” in 42nd AIAA Aerospace Sciences Meeting and Exhibit(AIAA, Reno, Nevada, 2004). [CrossRef]

].

In this paper, we performed the laser induced spark ignition of coaxial methane/oxygen/nitrogen diffusion flames to simulate the LSI behaviors on a model rocket engine with coaxial injectors. The MIE and ignition time of the LSI were determined, and the effects of gas mixture properties, including the overall Ф, oxygen concentration and flow rate, and ignition positions on the two parameters were investigated and discussed systematically.

2. Experimental apparatus

The experimental apparatus for the LSI of the coaxial methane/oxygen/nitrogen diffusion flames is shown in Fig. 1
Fig. 1 Experimental apparatus for the LSI of the methane/oxygen/nitrogen diffusion flames.
. It consists of three subsystems: the gas mixing and burner system, laser ignition and diagnostic system, and synchronization system.

The burner consists of two coaxial quartz tubes. The inner tube has an inner and outer diameter of 7.2 mm and 10 mm, respectively, while the annulus tube has an outer diameter of 12 mm. The detailed schematic of the coaxial burner is shown in Fig. 2
Fig. 2 Schematic of the coaxial burner and definition of the coordinate system.
. The oxygen and nitrogen is premixed to a specific oxygen concentration (χO2) which is defined as the mole concentration of the oxygen in the mixture of oxygen and nitrogen, and then flows into the inner tube. Pure methane (>99.5%) is introduced through the outer annulus tube. The flow rate and overall Ф of the gas mixture are controlled by three calibrated mass flow meters (D07-19B, Sevenstar electronics). To enable spatially resolved measurements, the burner is mounted on a three-dimensional translation stage that can be adjusted relative to the laser generated sparks.

For the diffusion flame, the ignition position is an important factor for a successful ignition, thus a coordinate system is introduced to address the ignition position. As shown in Fig. 2, the origin of the coordinates is fixed to the axis of the burner on the plane of the burner tip. The positive direction of the X axis is the same with the laser incidence direction. The positive direction of the Y axis is perpendicular to the X axis and to the right when facing the laser incidence direction. The Z axis is then determined using the right-handed coordinate system. The ignition position in the flow field is then given with the coordinates in the form of (X, Y, Z) throughout the whole paper.

A laser diode pumped Q-switched Nd:YAG laser (SpitLight DPSSL-250, Innolas) is used for the laser ignition measurements. The 1064 nm, ~10 nanosecond output of the laser is focused into the methane/oxygen/nitrogen gas flow using a 25mm diameter BK7 lens with a focal length of 150 mm to generate the laser sparks. Assuming that the focused laser beam around the focal spot is cylindrical with a Gaussian beam profile, the diameter and length of the focal region are estimated as 8.47 μm and 194.06 μm, respectively, using the formulas given by Beduneau et al. [25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

]. The laser is operated at a pulse rate of 2 Hz. The input laser pulse energy is measured with energy detector 1 (J-10MB-HE, Coherent) through a beam splitter with a 5% energy extraction. The residual energy after the generation of the laser sparks is measured with energy detector 2 (J-50MB-HE, Coherent). The output of the two energy meters is collected using a two-channel energy meter (EPM2000, Molectron) and read out through a RS232-USB interface. The spark energy is then calculated as the difference of the input energy and the residual energy.

The success or failure of the laser ignition events is determined by measuring the emission due to the ignited flames during the ignition processes. Typically, in the case of a successful ignition, a stable flame will be generated above the burner after firing of the laser spark, and strong flame emission can be observed. The flame emission is imaged onto the window of a fast photomultiplier tube (PMT, rise time < 2 ns) using a 25 mm diameter, 75 mm focal length BK7 lens. The PMT signal is amplified 25 times using a low noise four-channel preamplifier (SR445A, Stanford Research Systems) and then monitored and collected using a 1 GHz sampling rate digital storage oscilloscope (DPO7014, Tektronix). The PMT signal profiles are then read out and saved through a GPIB-USB port.

The synchronization of the whole measurement system is realized using a digital delay generator (DG645, Stanford Research Systems). The external triggers for the flashlamp and Q-Switch of the Nd:YAG laser, the energy meter, and the oscilloscope are all provided by the output of the delay generator. With the synchronization system, the spark energy and the PMT profile of each ignition event can be simultaneously obtained, enabling the correlation of the parameters with each other.

3. Results and discussions

3.1 Definitions and methods

The typical flame emission signal profile observed for a successful ignition event is shown in Fig. 3
Fig. 3 Determination of the success of the LSI and definition of the ignition time.
. The strong peak signal observed at the early time is due to the laser plasma emission which usually lasts for about 1-2 μs. It is shown that when the laser spark is generated in the gas mixture, there is a time gap before the flame emission signal emerges. The ignition time is then defined as the time gap between the onset of the laser spark and the time when the flame emission signal emerges.

3.2 MIE and ignition time of different gas mixture properties

3.2.1 Overall equivalence ratio effect

We measured the MIE and ignition time of the LSI of the methane/oxygen/nitrogen diffusion flames with different overall Ф in the range of 0.2-2.3. The ignition position is fixed to (3, 0, 15), the χO2 is fixed to 50%, and the total flow rate is fixed to 2.2 liter per minute (LPM). Shown in Fig. 4(a)
Fig. 4 MIE (a) and ignition time (b) of different overall equivalence ratios.
is the MIE of different overall Ф. The error bars shown in the figure are the standard deviation of the measured spark energies. It is shown that the MIE is around 4 mJ and varies little with the overall Ф of 0.5-2.3 and increases to ~7.5 mJ with the overall Ф of 0.3.

The MIE values obtained here are similar to the results obtained by Phuoc et al. [27

27. T. X. Phuoc, C. M. White, and D. H. McNeill, “Laser spark ignition of a jet diffusion flame,” Opt. Lasers Eng. 38(5), 217–232 (2002). [CrossRef]

] who reported a spark energy of ~4 mJ to successfully ignite a methane jet diffusion flame. However, the trend of the variation of the MIE with the overall Ф is different from the results obtained in the LSI of the premixed methane/air mixtures [8

8. T. X. Phuoc and F. X. White, “Laser-induced spark ignition of CH4/air mixtures,” Combust. Flame 119(3), 203–216 (1999). [CrossRef]

, 25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

, 30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

]. For the premixed methane/air mixtures, the variation of the MIE with the overall Ф is typically of U-shape, i.e., the MIE approaches its minimum value around the stoichiometry, but increases rapidly towards the fuel lean and rich ends [8

8. T. X. Phuoc and F. X. White, “Laser-induced spark ignition of CH4/air mixtures,” Combust. Flame 119(3), 203–216 (1999). [CrossRef]

, 25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

, 30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

]. The differences between the MIE values of the diffusion flame and the premixed flame is probably due to the deviation of the local Ф at the ignition spot from the nominal overall Ф set by the mass flow meters for the diffusion flame. In the reported relationship of MIE vs. Ф for the premixed methane/air mixtures, the MIE varies little with the Ф in the range of 1.058-1.68 [8

8. T. X. Phuoc and F. X. White, “Laser-induced spark ignition of CH4/air mixtures,” Combust. Flame 119(3), 203–216 (1999). [CrossRef]

] or 0.8-1.1 [30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

], depending on the burner systems applied. Meanwhile, the local Ф region for the invariant MIE might be expanded, since wider flammability limits have been reported in electric spark initiated ignition of the oxygen-enriched gas mixtures [31

31. B. Lewis and G. Von Elbe, Combustion, Flames and Explosions of Gases (Academic Press, 1987).

]. For the overall Ф in the range of 0.5-2.3, the local Ф may well within the invariant region, thus leading to an almost constant MIE value. When the overall Ф is too lean, the corresponding local Ф may approach the fuel lean end, and as reported in the LSI of premixed methane/air mixtures [8

8. T. X. Phuoc and F. X. White, “Laser-induced spark ignition of CH4/air mixtures,” Combust. Flame 119(3), 203–216 (1999). [CrossRef]

, 25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

, 30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

], the MIE will then increase accordingly. Detailed distributions of the local Ф in the diffusion flow field will be presented in section 3.3.

The ignition time of different overall Ф is shown in Fig. 4(b). It is shown that the minimum ignition time is obtained as ~200 μs with overall Ф of 0.6-1.0. When the overall Ф varies towards the fuel lean end, the ignition time firstly increases gradually to ~400 μs with overall Ф of 0.4-0.5 and then increases quickly to ~1800 μs with overall Ф of 0.2. The variation of the ignition time with the overall Ф to the fuel rich end has a different trend. The ignition time varies little with the Ф in the range 1.1-2.0, and keeps at around 400 μs. The ignition time reported here is about one order of magnitude lower than that obtained by Phuoc et al. [27

27. T. X. Phuoc, C. M. White, and D. H. McNeill, “Laser spark ignition of a jet diffusion flame,” Opt. Lasers Eng. 38(5), 217–232 (2002). [CrossRef]

] and Li et al. [30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

]. This is probably due to the relatively higher oxygen concentration in the gas mixture: the χO2 is 50% in the measurements presented in this work, while both Phuoc et al. [27

27. T. X. Phuoc, C. M. White, and D. H. McNeill, “Laser spark ignition of a jet diffusion flame,” Opt. Lasers Eng. 38(5), 217–232 (2002). [CrossRef]

] and Li et al. [30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

] used a χO2 of 21% . Actually, the ignition time of methane/oxygen mixtures has been investigated in a shock-tube facility [32

32. A. Lifshitz, K. Scheller, A. Burcat, and G. B. Skinner, “Shock-tube investigation of ignition in methane-oxygen-argon mixtures,” Combust. Flame 16(3), 311–321 (1971). [CrossRef]

]. Ignition time of 10-600 μs was obtained and the ignition time (τ) was reported to be approximately inversely proportional to the oxygen mole concentration in the gas mixture ([O2]) with a relationship of τ∝[O2]-1.03, which again indicates that higher χO2 might lead to a shorter ignition time.

3.2.2 Oxygen concentration effect

The MIE and ignition time of the LSI of the methane/oxygen/nitrogen diffusion flames with different oxygen concentrations of the oxygen/nitrogen mixture are shown in Fig. 5
Fig. 5 MIE (a) and ignition time (b) of different oxygen concentrations.
. The ignition position is fixed to (3, 0, 10). The flow rate is fixed to 2.2 LPM. The overall Ф are 0.7, 1.0 and 1.3, respectively, and the χO2 is 20%, 40% and 60%, respectively. It is shown that for all the three overall Ф, the MIE does not have a specific trend with the increasing oxygen concentration. The MIE values of different oxygen concentrations are comparable with each other. However, the ignition time has a clear trend with the increasing oxygen concentration. It decreases gradually with the increase of the oxygen concentration. The decrease of the ignition time may be due to the reduced dilution effect of the nitrogen when the oxygen concentration is high.

3.2.3 Flow rate effect

The MIE and ignition time of the LSI of the methane/oxygen/nitrogen diffusion flames with different flow rates are shown in Fig. 6
Fig. 6 MIE (a) and ignition time (b) of different flow rates.
. The ignition position is set to (3, 0, 10). The χO2 is fixed to 50%. The overall Ф are 0.7, 1.0, and 1.3, respectively, and the total flow rates are varied from 2.2 LPM to 4.4 LPM. The flow velocities at the ignition position are estimated as 68-153 cm/s from the gas flow velocities in the inner tube. According to Spiglanin et al. [2

2. T. A. Spiglanin, A. Mcilroy, E. W. Fournier, R. B. Cohen, and J. A. Syage, “Time-resolved imaging of flame kernels: laser spark ignition of H2/O2/Ar mixtures,” Combust. Flame 102(3), 310–328 (1995). [CrossRef]

] and Beduneau et al. [25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

], the gas flow can be considered as stagnant during the laser spark generation and flame kernel formation processes, which have a typical expansion speed of the order of 105-106 cm/s [3

3. T. X. Phuoc, “Laser-induced spark ignition fundamental and applications,” Opt. Lasers Eng. 44(5), 351–397 (2006). [CrossRef]

] and 104 cm/s [25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

], respectively. Thus the gas flow should have little effect on the laser spark formation. It is shown that the MIE values are comparable with each other for all the flow rates investigated. The MIE values of different overall Ф are also comparable with each other, which is consistent with the results shown in Fig. 4(a). However, the ignition time is sensitive to the variation of the flow rates. The ignition time increases gradually with the increasing flow rates. The higher flow rates may cause more convection losses in the flame kernel [25

25. J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

], and lead to a lower initial flame kernel temperature. The lower initial temperature then lengthens the time needed to reach the critical ignition temperature, thus resulting a longer ignition time.

3.3 MIE and ignition time of different ignition positions

For diffusion flames, since the fuel and oxidant diffuses and mixes with each other, the local mixing condition at different spatial positions relative to the burner assembly will vary greatly. Therefore, the ignition position can affect the MIE and ignition time greatly.

The MIE and the ignition time of different ignition positions are measured by adjusting the burner assembly relative to the formed laser sparks. The total flow rate is fixed to 2.2 LPM. The overall Ф is set to 1.0, and the χO2 is set to 50%. During the measurements, the Y coordinate is set to 0, i.e., the laser passes through the center of the inner tube (refer to the illustration of the coordinates system shown in Fig. 2). The horizontal position (X coordinate) is varied in the range of 0-5 mm, i.e., from the burner axis to the outer diameter of the inner tube. The vertical position (Z coordinate) is varied in the range of 1-11 mm. The measurements are performed in the XOZ plane with a spatial grid size of 1 mm × 1 mm, and the contour distributions of the MIE and ignition time are obtained.

The contour plot of the ignition time at different ignition positions is shown in Fig. 8
Fig. 8 Contour plot of the ignition time values at different ignition positions.
. It is shown that the shortest ignition time is obtained as less than 140 μs in the region with X coordinates of 3.0-4.0 mm and Z coordinates of 2.5-5.0 mm. Then the ignition time increases gradually towards the smaller and larger X coordinates, especially for the latter case. The longest ignition time is obtained as ~2800 μs in the region with X coordinates of 4.5-5.0 mm and Z coordinates of 5.0-8.0 mm.

The detailed distributions of the mole fraction of oxygen, mole fraction of methane and local Ф in the diffusion flow field are simulated based on computational fluid dynamics (CFD) calculations. As shown in Fig. 9
Fig. 9 Simulated contour distributions of the mole fraction of oxygen (a), mole fraction of methane (b) and local equivalence ratio in the diffusion flow field. The flow rate is 2.2 LPM, the overall Ф is 1.0, and the χO2 is 50%.
, the simulation is performed in the spatial regions with X coordinates of 0-20 mm and Z coordinates of 0-96 mm. The flow conditions are the same with that of Fig. 7 and Fig. 8, i.e., the flow rate is 2.2 LPM, the overall Ф is 1.0, and the χO2 is 50%. Since the burner is axisymmetric, only the distribution on half of the XOZ plane is given. It is shown in Fig. 9(a) that the oxygen mole fraction approaches its highest value in the region near the burner axis and then decreases gradually when the ignition position moves vertically up along the burner axis or away from the burner axis. The lowest oxygen mole fraction is located in the region near the methane outlet. While for the methane flow (see Fig. 9(b)), the highest mole fraction values are obtained near the methane outlet and then it decreases gradually with the diffusion of the methane. The local Ф are calculated using the simulated mole fraction distributions of the oxygen and methane. As shown in Fig. 9(c), there are great variations in the local Ф of the diffusion flow field. The highest local Ф (>10) is obtained near the methane outlet with X coordinates of 5-6 mm. Then the local Ф decreases gradually when the ignition position moves outwards from the methane outlet, due to the diffusion and mixing of the methane flow with both the oxidant flow and the ambient air. The lowest local Ф (~zero) is obtained in the region near the burner axis where the oxidant flow outlet locates and in the regions far beyond the methane outlet. It can be seen that the simulated distribution of the local Ф in the flow field are generally consistent with our above qualitative estimations.

3.4 Discussions

The local mixing condition within the flow field of the coaxial methane/oxygen/nitrogen diffusion flames can affect the ignition properties to a large extent. The simulation based on the CFD calculations can offer a general estimation on the local mixing conditions in the flow field and explain most of the experimental results. However, it is fair to point out that the CFD calculation presented here has its limitations. It seems that the local Ф are underestimated by the CFD calculations, especially in the regions near the burner axis. In the region with X coordinates of 1-2 mm and Z coordinates of 1-10 mm, the gas mixture would be unable to be ignited with the very low calculated local Ф values, which contradicts the measured results.

Accurate measurement of the local Ф can offset the limitations of the CFD model. Laser induced breakdown spectroscopy (LIBS) technique has been applied for the local Ф measurements [27

27. T. X. Phuoc, C. M. White, and D. H. McNeill, “Laser spark ignition of a jet diffusion flame,” Opt. Lasers Eng. 38(5), 217–232 (2002). [CrossRef]

,30

30. X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

,33

33. F. Ferioli, P. V. Puzinauskas, and S. G. Buckley, “Laser-induced breakdown spectroscopy for on-line engine equivalence ratio measurements,” Appl. Spectrosc. 57(9), 1183–1189 (2003). [CrossRef] [PubMed]

,34

34. J. Kiefer, J. W. Tröger, Z. S. Li, and M. Aldén, “Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics,” Appl. Phys. B 103(1), 229–236 (2011). [CrossRef]

]. By correlating the local Ф with the intensity ratio of two atomic lines originating from the elements of the fuel and oxidant, respectively, the local Ф can be obtained. We have tried to measure the local Ф by using the line intensity ratio of Hα line to the nitrogen atomic triplet lines around 742 nm or to the oxygen atomic triplet lines around 777 nm. However, due to the limitations of our spectrograph system, the above atomic emissions cannot be collected in the same detection window, and thus cannot be measured simultaneously. Therefore, the local Ф was not measured in the present paper. Work to reconstruct another spectrograph system with wider detection window is now in progress, and the local Ф can then be obtained.

It should also be noted that the MIE values shown in Fig. 4(a) is lower than those shown in other figures. We think this is mainly due to its relatively higher ignition position. The ignition position in Fig. 4(a) is at (3, 0, 15). At the higher ignition position, the local Ф may be more close to the stoichiometry and thus lower MIE values were obtained.

4. Conclusions

Laser spark ignition (LSI) of coaxial methane/oxygen/nitrogen diffusion flames has been achieved using a 1064 nm Q-switched Nd:YAG laser. The minimum ignition energy (MIE) and ignition time of the LSI have been obtained by measuring the emission signals due to the ignited flames. The effects of the gas mixture properties, including the overall equivalence ratio (Ф), oxygen concentration, and flow rate, and the ignition positions on the MIE and ignition time have been investigated systematically. Several conclusions draw from our investigations can be summarized as follows:

(i) Computational fluid dynamics (CFD) simulations indicate that the local Ф varies greatly within the diffusion flow field. The local Ф approaches its maximum value near the methane outlet, and then decreases gradually when the ignition position moves outwards from the methane outlet, due to the diffusion and mixing of the methane flow with both the oxidant flow and the ambient air. The lowest local Ф is obtained in the region near the burner axis and far beyond the methane outlet.

(iii) For the ignitions at (3, 0, 15), the MIE is around 4 mJ and varies little with the overall Ф of 0.5-2.3 and increases to ~7.5 mJ with overall Ф of 0.3. The ignition time approaches it minimum value ~200 μs with overall Ф of 0.6-1.0, and increases to ~400 μs with Ф of 0.4-0.5 and 1.1-2.0, and further to ~1800 μs towards the fuel lean end.

(iv) For the ignitions at (3, 0, 10), the oxygen concentration and flow rate has little effect on the MIE. The ignition time decreases gradually with the increasing oxygen concentration, while increases gradually with the increasing flow rate.

The MIE and ignition time values obtained for the LSI of the coaxial diffusion flames can serve as references for design and evaluation of the LSI system for the model rocket engines using coaxial injectors.

Acknowledgments

The authors thank the financial support from the National Natural Science Foundation of China (Grant No.61275127) and Special Grants for National Key Scientific Instrument and Equipment Development (Project No.2012YQ040164).

References and links

1.

P. D. Ronney, “Laser versus conventional ignition of flames,” Opt. Eng. 33(2), 510–521 (1994). [CrossRef]

2.

T. A. Spiglanin, A. Mcilroy, E. W. Fournier, R. B. Cohen, and J. A. Syage, “Time-resolved imaging of flame kernels: laser spark ignition of H2/O2/Ar mixtures,” Combust. Flame 102(3), 310–328 (1995). [CrossRef]

3.

T. X. Phuoc, “Laser-induced spark ignition fundamental and applications,” Opt. Lasers Eng. 44(5), 351–397 (2006). [CrossRef]

4.

D. Bradley, C. G. W. Sheppard, I. M. Suardjaja, and R. Woolley, “Fundamentals of high-energy spark ignition with lasers,” Combust. Flame 138(1-2), 55–77 (2004). [CrossRef]

5.

M. Weinrotter, H. Kopecek, E. Wintner, M. Lackner, and F. Winter, “Application of laser ignition to hydrogen-air mixtures at high pressures,” Int. J. Hydrogen Energy 30(3), 319–326 (2005). [CrossRef]

6.

L. Zimmer, K. Okai, and Y. Kurosawa, “Combined laser induced ignition and plasma spectroscopy: fundamentals and application to a hydrogen-air combustor,” Spectrochim. Acta, B At. Spectrosc. 62(12), 1484–1495 (2007). [CrossRef]

7.

J. L. Beduneau, N. Kawahara, T. Nakayama, E. Tomita, and Y. Ikeda, “Laser-induced radical generation and evolution to a self-sustaining flame,” Combust. Flame 156(3), 642–656 (2009). [CrossRef]

8.

T. X. Phuoc and F. X. White, “Laser-induced spark ignition of CH4/air mixtures,” Combust. Flame 119(3), 203–216 (1999). [CrossRef]

9.

M. H. Morsy and S. H. Chung, “Laser-induced multi-point ignition with a single-shot laser using two conical cavities for hydrogen/air mixture,” Exp. Therm. Fluid Sci. 27(4), 491–497 (2003). [CrossRef]

10.

J. X. Ma, D. R. Alexander, and D. E. Poulain, “Laser spark ignition and combustion characteristics of methane-air mixtures,” Combust. Flame 112(4), 492–506 (1998). [CrossRef]

11.

G. Herdin, J. Klausner, E. Wintner, M. Weinrotter, J. Graf, and K. Iskra, “Laser ignition - a new concept to use and increase the pontentials of gas engines,” in ASME Internal Combustion Engine Division 2005 Fall Technical Conference:AERS-ARICE Symposium on Gas Fired Reciprocating Engines(Ottawa, Canada, 2005).

12.

Y.-L. Chen and J. W. L. Lewis, “Visualization of laser-induced breakdown and ignition,” Opt. Express 9(7), 360–372 (2001). [CrossRef] [PubMed]

13.

M. Lackner, S. Charareh, F. Winter, K. Iskra, D. Rüdisser, T. Neger, H. Kopecek, and E. Wintner, “Investigation of the early stages in laser-induced ignition by Schlieren photography and laser-induced fluorescence spectroscopy,” Opt. Express 12(19), 4546–4557 (2004). [CrossRef] [PubMed]

14.

N. Pavel, M. Tsunekane, and T. Taira, “Composite, all-ceramics, high-peak power Nd:YAG/Cr4+:YAG monolithic micro-laser with multiple-beam output for engine ignition,” Opt. Express 19(10), 9378–9384 (2011). [CrossRef] [PubMed]

15.

G. Liedl, D. Schuocker, B. Geringer, J. Graf, D. Klawatsch, H. P. Lenz, W. F. Piock, M. Jetzinger, and P. Kapus, “Laser induced ignition of gasoline direct injection engines,” Proc. SPIE 5777, 955–959 (2004).

16.

S. Brieschenk, S. O’Byrne, and H. Kleine, “Laser-induced plasma ignition studies in a model scramjet engine,” Combust. Flame 160(1), 145–148 (2013). [CrossRef]

17.

R. J. Osborne, J. A. Wehrmeyer, H. P. Trinh, and J. W. Early, “Evaluation and characterization study of dual pulse laser-induced spark(DPLIS) for rocket engine ignition system application,” in 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit(AIAA Huntsville, Alabama, 2003), paper 2003–4905. [CrossRef]

18.

T. Razafimandimby, M. De Rosa, V. Schmidt, J. Sender, and M. Oschwald, “Laser ignition of a GH2/LOX spray under vacuum conditions,” in The European Combustion Meeting(2005), pp. 1–6.

19.

K. Hasegawa, K. Kusaka, A. Kumakawa, M. Sato, and M. Tadano, “Laser ignition characteristics of GOX/GH2 and GOX/GCH4 propellants,” in 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit(AIAA, Huntsville, Alabama, 2003), paper 2003–4906. [CrossRef]

20.

L. C. Liou, “Laser ignition in liquid rocket engines,” in 30th AIAA/SAE/ASME/ASEE Joint Propulsion Conference(AIAA, Indianapolis, IN, 1994), paper 94–2980.

21.

F. B. Carleton, N. Klein, K. Krallis, and F. J. Weinberg, “Laser ignition of liquid propellants,” Symposium (International) on Combustion 23, 1323–1329 (1991). [CrossRef]

22.

M. De Rosa, J. Sender, H. Zimmermann, and M. Oschwald, “Cryogenic spary ignition at high altitude conditions,” in 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit(AIAA, Sacramento, CA, 2006), paper 2006–4539. [CrossRef]

23.

C. Pauly, J. Sender, and M. Oschwald, “Ignition of a gaseous methane/oxygen coaxial jet,” Prog. Propulsion Phys. 1, 155–170 (2009).

24.

V. Schmidt, U. Wepler, O. Haidn, and M. Oschwald, “Characterization of the primary ignition process of a coaxial GH2/LOx spray,” in 42nd AIAA Aerospace Sciences Meeting and Exhibit(AIAA, Reno, Nevada, 2004). [CrossRef]

25.

J. L. Beduneau, B. Kim, L. Zimmer, and Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]

26.

H. Kopecek, H. Maier, G. Reider, F. Winter, and E. Wintner, “Laser ignition of methane-air mixtures at high pressures,” Exp. Therm. Fluid Sci. 27(4), 499–503 (2003). [CrossRef]

27.

T. X. Phuoc, C. M. White, and D. H. McNeill, “Laser spark ignition of a jet diffusion flame,” Opt. Lasers Eng. 38(5), 217–232 (2002). [CrossRef]

28.

F. B. Carleton, N. Klein, K. Krallis, and F. J. Weinberg, “Laser ignition of liquid propellants,” Twenty third symposium (International) on combustion 23, 1323–1329 (1991). [CrossRef]

29.

T.-W. Lee, V. Jain, and S. Kozola, “Measurements of minimum ignition energy by using laser sparks for hydrocarbon fuels in air: propane, dodecane, and jet-A fuel,” Combust. Flame 125(4), 1320–1328 (2001). [CrossRef]

30.

X. Li, B. W. Smith, and N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.

31.

B. Lewis and G. Von Elbe, Combustion, Flames and Explosions of Gases (Academic Press, 1987).

32.

A. Lifshitz, K. Scheller, A. Burcat, and G. B. Skinner, “Shock-tube investigation of ignition in methane-oxygen-argon mixtures,” Combust. Flame 16(3), 311–321 (1971). [CrossRef]

33.

F. Ferioli, P. V. Puzinauskas, and S. G. Buckley, “Laser-induced breakdown spectroscopy for on-line engine equivalence ratio measurements,” Appl. Spectrosc. 57(9), 1183–1189 (2003). [CrossRef] [PubMed]

34.

J. Kiefer, J. W. Tröger, Z. S. Li, and M. Aldén, “Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics,” Appl. Phys. B 103(1), 229–236 (2011). [CrossRef]

OCIS Codes
(140.3440) Lasers and laser optics : Laser-induced breakdown
(280.1740) Remote sensing and sensors : Combustion diagnostics
(300.2140) Spectroscopy : Emission

ToC Category:
Optical Devices

History
Original Manuscript: October 1, 2013
Revised Manuscript: November 15, 2013
Manuscript Accepted: January 14, 2014
Published: February 6, 2014

Citation
Xiaohui Li, Yang Yu, Xin Yu, Chang Liu, Rongwei Fan, and Deying Chen, "Laser induced spark ignition of coaxial methane/oxygen/nitrogen diffusion flames," Opt. Express 22, 3447-3457 (2014)
http://www.opticsinfobase.org/oe/abstract.cfm?URI=oe-22-3-3447


Sort:  Author  |  Year  |  Journal  |  Reset  

References

  1. P. D. Ronney, “Laser versus conventional ignition of flames,” Opt. Eng. 33(2), 510–521 (1994). [CrossRef]
  2. T. A. Spiglanin, A. Mcilroy, E. W. Fournier, R. B. Cohen, J. A. Syage, “Time-resolved imaging of flame kernels: laser spark ignition of H2/O2/Ar mixtures,” Combust. Flame 102(3), 310–328 (1995). [CrossRef]
  3. T. X. Phuoc, “Laser-induced spark ignition fundamental and applications,” Opt. Lasers Eng. 44(5), 351–397 (2006). [CrossRef]
  4. D. Bradley, C. G. W. Sheppard, I. M. Suardjaja, R. Woolley, “Fundamentals of high-energy spark ignition with lasers,” Combust. Flame 138(1-2), 55–77 (2004). [CrossRef]
  5. M. Weinrotter, H. Kopecek, E. Wintner, M. Lackner, F. Winter, “Application of laser ignition to hydrogen-air mixtures at high pressures,” Int. J. Hydrogen Energy 30(3), 319–326 (2005). [CrossRef]
  6. L. Zimmer, K. Okai, Y. Kurosawa, “Combined laser induced ignition and plasma spectroscopy: fundamentals and application to a hydrogen-air combustor,” Spectrochim. Acta, B At. Spectrosc. 62(12), 1484–1495 (2007). [CrossRef]
  7. J. L. Beduneau, N. Kawahara, T. Nakayama, E. Tomita, Y. Ikeda, “Laser-induced radical generation and evolution to a self-sustaining flame,” Combust. Flame 156(3), 642–656 (2009). [CrossRef]
  8. T. X. Phuoc, F. X. White, “Laser-induced spark ignition of CH4/air mixtures,” Combust. Flame 119(3), 203–216 (1999). [CrossRef]
  9. M. H. Morsy, S. H. Chung, “Laser-induced multi-point ignition with a single-shot laser using two conical cavities for hydrogen/air mixture,” Exp. Therm. Fluid Sci. 27(4), 491–497 (2003). [CrossRef]
  10. J. X. Ma, D. R. Alexander, D. E. Poulain, “Laser spark ignition and combustion characteristics of methane-air mixtures,” Combust. Flame 112(4), 492–506 (1998). [CrossRef]
  11. G. Herdin, J. Klausner, E. Wintner, M. Weinrotter, J. Graf, and K. Iskra, “Laser ignition - a new concept to use and increase the pontentials of gas engines,” in ASME Internal Combustion Engine Division 2005 Fall Technical Conference:AERS-ARICE Symposium on Gas Fired Reciprocating Engines(Ottawa, Canada, 2005).
  12. Y.-L. Chen, J. W. L. Lewis, “Visualization of laser-induced breakdown and ignition,” Opt. Express 9(7), 360–372 (2001). [CrossRef] [PubMed]
  13. M. Lackner, S. Charareh, F. Winter, K. Iskra, D. Rüdisser, T. Neger, H. Kopecek, E. Wintner, “Investigation of the early stages in laser-induced ignition by Schlieren photography and laser-induced fluorescence spectroscopy,” Opt. Express 12(19), 4546–4557 (2004). [CrossRef] [PubMed]
  14. N. Pavel, M. Tsunekane, T. Taira, “Composite, all-ceramics, high-peak power Nd:YAG/Cr4+:YAG monolithic micro-laser with multiple-beam output for engine ignition,” Opt. Express 19(10), 9378–9384 (2011). [CrossRef] [PubMed]
  15. G. Liedl, D. Schuocker, B. Geringer, J. Graf, D. Klawatsch, H. P. Lenz, W. F. Piock, M. Jetzinger, P. Kapus, “Laser induced ignition of gasoline direct injection engines,” Proc. SPIE 5777, 955–959 (2004).
  16. S. Brieschenk, S. O’Byrne, H. Kleine, “Laser-induced plasma ignition studies in a model scramjet engine,” Combust. Flame 160(1), 145–148 (2013). [CrossRef]
  17. R. J. Osborne, J. A. Wehrmeyer, H. P. Trinh, and J. W. Early, “Evaluation and characterization study of dual pulse laser-induced spark(DPLIS) for rocket engine ignition system application,” in 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit(AIAA Huntsville, Alabama, 2003), paper 2003–4905. [CrossRef]
  18. T. Razafimandimby, M. De Rosa, V. Schmidt, J. Sender, and M. Oschwald, “Laser ignition of a GH2/LOX spray under vacuum conditions,” in The European Combustion Meeting(2005), pp. 1–6.
  19. K. Hasegawa, K. Kusaka, A. Kumakawa, M. Sato, and M. Tadano, “Laser ignition characteristics of GOX/GH2 and GOX/GCH4 propellants,” in 39th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit(AIAA, Huntsville, Alabama, 2003), paper 2003–4906. [CrossRef]
  20. L. C. Liou, “Laser ignition in liquid rocket engines,” in 30th AIAA/SAE/ASME/ASEE Joint Propulsion Conference(AIAA, Indianapolis, IN, 1994), paper 94–2980.
  21. F. B. Carleton, N. Klein, K. Krallis, and F. J. Weinberg, “Laser ignition of liquid propellants,” Symposium (International) on Combustion 23, 1323–1329 (1991). [CrossRef]
  22. M. De Rosa, J. Sender, H. Zimmermann, and M. Oschwald, “Cryogenic spary ignition at high altitude conditions,” in 42nd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit(AIAA, Sacramento, CA, 2006), paper 2006–4539. [CrossRef]
  23. C. Pauly, J. Sender, M. Oschwald, “Ignition of a gaseous methane/oxygen coaxial jet,” Prog. Propulsion Phys. 1, 155–170 (2009).
  24. V. Schmidt, U. Wepler, O. Haidn, and M. Oschwald, “Characterization of the primary ignition process of a coaxial GH2/LOx spray,” in 42nd AIAA Aerospace Sciences Meeting and Exhibit(AIAA, Reno, Nevada, 2004). [CrossRef]
  25. J. L. Beduneau, B. Kim, L. Zimmer, Y. Ikeda, “Measurements of minimum ignition energy in premixed laminar methane/air flow by using laser induced spark,” Combust. Flame 132(4), 653–665 (2003). [CrossRef]
  26. H. Kopecek, H. Maier, G. Reider, F. Winter, E. Wintner, “Laser ignition of methane-air mixtures at high pressures,” Exp. Therm. Fluid Sci. 27(4), 499–503 (2003). [CrossRef]
  27. T. X. Phuoc, C. M. White, D. H. McNeill, “Laser spark ignition of a jet diffusion flame,” Opt. Lasers Eng. 38(5), 217–232 (2002). [CrossRef]
  28. F. B. Carleton, N. Klein, K. Krallis, and F. J. Weinberg, “Laser ignition of liquid propellants,” Twenty third symposium (International) on combustion 23, 1323–1329 (1991). [CrossRef]
  29. T.-W. Lee, V. Jain, S. Kozola, “Measurements of minimum ignition energy by using laser sparks for hydrocarbon fuels in air: propane, dodecane, and jet-A fuel,” Combust. Flame 125(4), 1320–1328 (2001). [CrossRef]
  30. X. Li, B. W. Smith, N. Omenetto, “Laser spark ignition of premixed methane/air mixtures: parameter measurements and determination of key factors for ultimate ignition results,” Combust. Flame. Submitted.
  31. B. Lewis and G. Von Elbe, Combustion, Flames and Explosions of Gases (Academic Press, 1987).
  32. A. Lifshitz, K. Scheller, A. Burcat, G. B. Skinner, “Shock-tube investigation of ignition in methane-oxygen-argon mixtures,” Combust. Flame 16(3), 311–321 (1971). [CrossRef]
  33. F. Ferioli, P. V. Puzinauskas, S. G. Buckley, “Laser-induced breakdown spectroscopy for on-line engine equivalence ratio measurements,” Appl. Spectrosc. 57(9), 1183–1189 (2003). [CrossRef] [PubMed]
  34. J. Kiefer, J. W. Tröger, Z. S. Li, M. Aldén, “Laser-induced plasma in methane and dimethyl ether for flame ignition and combustion diagnostics,” Appl. Phys. B 103(1), 229–236 (2011). [CrossRef]

Cited By

Alert me when this paper is cited

OSA is able to provide readers links to articles that cite this paper by participating in CrossRef's Cited-By Linking service. CrossRef includes content from more than 3000 publishers and societies. In addition to listing OSA journal articles that cite this paper, citing articles from other participating publishers will also be listed.


« Previous Article  |  Next Article »

OSA is a member of CrossRef.

CrossCheck Deposited