Development of scale-controlled premixed turbulent burner and the flame structure analysis
-
摘要: 为了研究单一湍流场参数对预混湍流火焰结构的影响，以及拓宽湍流场的强度和尺度范围，发展了一套可变结构的预混湍流燃烧器。采用恒温型热线风速仪标定流场，得到了一系列湍流参数。流场标定结果表明：该燃烧器能显著拓宽湍流强度和尺度范围，并能利用不同几何结构产生多种可控流场，实现研究单一湍流参数对湍流燃烧速度和火焰结构影响的目的。选用有代表性的15种湍流孔板组合结构，利用OH-PLIF燃烧激光诊断技术，开展了湍流燃烧实验，结果表明：湍流强度的增大（1 < u'/SL，0 < 10）使得湍流火焰分区扩展到了薄层反应区，火焰面破碎程度明显增强，孤岛结构明显增多。高宏观雷诺数下，积分尺度的增长对湍流燃烧速度起抑制作用，可能存在临界宏观雷诺数Rec，能够表现流体惯性力占主导地位的程度，决定积分尺度对湍流燃烧速度的影响效果。积分尺度能量大，扰动能力强，故积分尺度越大，火焰体积越大；但过高的湍流强度会使火焰面褶皱更加剧烈，小尺度叠加在大尺度上的程度增强，最终也使火焰体积显著增大，掩盖了积分尺度对火焰体积的影响，说明积分尺度（表征大尺度）不如湍流强度（表征叠加小尺度的程度）对火焰放热率影响大。Abstract: The structure-variable premixed turbulent burner is developed to investigate the effects of single turbulence parameters on flame structure, and to broaden turbulence intensity and scale range. Hot-wire anemometer measurements of cold flow indicate that the burner can utilize different geometry structures to produce scale-controlled flow field and realize the investigation of the effects of single turbulence parameters on flame structure. Fifteen representative structures were selected for the premixed turbulent combustion experiment. OH-PLIF images show that high turbulence intensity enhances flame surface wrinkling, as well as increasing the number of island structures. Data are reported at 1 < u'/SL, 0 < 10 for CH4/air flames with equivalence ratio of 0.7 in the thin reaction zones. Increasing integral scale decreases the turbulent burning velocity at high Reynold number. There may exist a critical Rec which can represent the degree of how inertial forces are dominant to determine the effect of the integral scale on the turbulent burning velocity. Increasing the integral scale can also enlarge the flame volume, due to larger vortex containing higher energy. However, intensive turbulence intensity can wrinkle the flame surface much more remarkably, resulting in superposition of small scales on large scales. Therefore, the increasing turbulence intensity increases the flame volume more significantly, covering up the impact of integral scale on flame volume. These results indicate that the effect of integral scale (represent large scale) on the flame heat release rate is less significant than the effect of turbulence intensity (represent superposition degree of small scales on large scales).
-
图 6 结构S3_A本生灯出口中心点湍流能谱(U=3m/s)
Figure 6. Turbulence spectrum of structure S3_A (U=3m/s)
图 7 相对湍流强度随孔板种类及开孔比的变化关系(U=3m/s)
Figure 7. Relative turbulence intensity(u′/U) variations with plates type and opening ratio(U=3m/s)
图 8 单双层孔板的湍流强度随来流速度的变化
Figure 8. Turbulence intensity (u′) variations with bulk velocity (U) of single/double-layer structures
图 9 无量纲化湍动能的轴向变化
Figure 9. Normalized turbulence kinetic energy (k2/U2) as a function of axial distance from plates
图 10 相同本生灯结构的积分尺度随湍流强度的变化(通过改变来流速度改变湍流强度)
Figure 10. Integral scale (l0) variations with turbulence intensity (u′) of the same Bunsen burner structures (u′ is changed by bulk velocity U)
图 11 不同本生灯结构的积分尺度随湍流强度的变化(U=2m/s)
Figure 11. Integral scale (l0) variations with turbulence intensity (u′) of different Bunsen burner structures (U=2m/s)
图 12 U=3m/s时，当量比0.7的甲烷/空气的OH-PLIF图像
Figure 12. OH-PLIF images of CH4/air (Phi=0.7) when U=3m/s
图 13 U=5m/s时，当量比0.7的甲烷/空气的OH-PLIF图像
Figure 13. OH-PLIF images of CH4/air (Phi=0.7) when U=5m/s
图 15 湍流燃烧速度ST, GC/SL随湍流强度u′/SL变化关系
Figure 15. Turbulent flame speed (ST, GC) variations with turbulence intensity (u′) normalized by SL, 0 at various bulk velocities and integral scales
图 16 预混湍流火焰后处理过程：(a)原始图片；(b)二值化图片；(c)火焰前锋面；(d) 100张前锋面叠加的火焰刷; (e) 500张叠加的火焰前锋面；(f)平均进展变量 <c>
Figure 16. Post-processing of premixed turbulent flame:(a) original images; (b) binary images; (c) flame surface; (d) flame brush superposed by 100 images; (e) flame brush superposed by 500 images; (f) mean progress variable <c>
图 17 积分尺度和湍流强度对火焰体积的影响(U=3m/s)
Figure 17. Effects of integral scale (l0) and turbulence intensity (u′) on flame volume(U=3m/s)
表 1 不同孔板的开孔比
Table 1. Open ratio of different plate types
Plate type P1 P2 P3 P4 P5 Open ratio/% 54.3 63.5 55.5 37.1 43.8 Plate type S1 S2 S3 S4 Open ratio/% 17.1 25.7 38.5 51.3 
下载: 导出CSV
表 2 代表性结构的本生灯出口流场参数
Table 2. Flow field parameters of representative Bunsen burner structures
U
/(m·s-1)u′
/(m·s-1)Structures Integral
scale
l0/mmTaylor
scale
lλ/mmKolmogorov
scale
lk/mm3 0.96 S1_D_S1_A 5.327 0.285 0.06 0.96 S1_B_S1_A 6.821 0.322 0.065 0.74 S1_D 5.573 0.336 0.075 0.56 S3_A 3.983 0.332 0.087 0.56 S2_D 5.459 0.375 0.090 0.27 P5_D 4.504 0.497 0.151 0.27 P1_A 3.191 0.435 0.148 5 1.78 S1_D_S1_A 4.852 0.203 0.038 1.79 S1_B_S1_A 6.494 0.233 0.040 1.21 S3_A 4.323 0.232 0.049 1.25 S1_D 5.880 0.259 0.049 0.70 S4_A 3.309 0.267 0.069 0.26 P2_D 3.342 0.457 0.157 0.47 P3_A 2.929 0.304 0.089 0.45 P5_D 4.153 0.375 0.102
下载: 导出CSV
-
[1] Peters N. Turbulent combustion[M]. Cambridge:Cambridge University Press, 2000. [2] Lipatnikov A. Fundamentals of premixed turbulent combustion[M]. Abingdon:Taylor & Francis Group, 2013. [3] Leisenheimer B, Leuckel W. Self-generated acceleration of confined deflagrative flame fronts[J]. Combustion Science and Technology, 1996, 118(1-3):147-164. doi: 10.1080/00102209608951976 [4] Ballal D R. The structure of a premixed turbulent flame[J]. Proceedings of the Royal Society of London, 1979, 367(1730):353-380. doi: 10.1098/rspa.1979.0093 [5] Li S C, Libby P A, Williams F A. Experimental investigation of a premixed flame in an impinging turbulent stream[J]. Symposium on Combustion, 1994, 25(1):1207-1214. doi: 10.1016/S0082-0784(06)80760-5 [6] Shepherd I G, Bourguignon E, Michou Y, et al. The burning rate in turbulent bunsen flames[J]. Symposium on Combustion, 1998, 27(1):909-916. doi: 10.1016/S0082-0784(98)80488-8 [7] Ting D S K, Checkel M D, Haley R, et al. Early flame acceleration measurements in a turbulent spark-ignited mixture[R]. SAE Technical Paper 940687, 1994. [8] Yoshida A, Tsuji H. Characteristic scale of wrinkles in turbulent premixed flames[J]. Symposium on Combustion, 1982, 19(1):403-411. doi: 10.1016/S0082-0784(82)80212-9 [9] Kobayashi H, Kawahata T, Seyama K, et al. Relationship between the smallest scale of flame wrinkles and turbulence characteristics of high-pressure, high-temperature turbulent premixed flames[J]. Proceedings of the Combustion Institute, 2002, 29(2):1793-1800. doi: 10.1016/S1540-7489(02)80217-6 [10] Lawn C J, Schefer R W. Scaling of premixed turbulent flames in the corrugated regime[J]. Combustion and Flame, 2006, 146(1-2):180-199. doi: 10.1016/j.combustflame.2006.03.010 [11] Tanahashi M, Yu Y, Miyauchi T. Effects of turbulence characteristic length scale on hydrogen-air turbulent premixed flames[J]. Thermal Science and Engineering, 2001, 9:39-48. doi: 10.1007%2Fs12206-009-0409-1 [12] Yu Y, Tanahashi M, Miyauchi T. Relation between turbulence characteristic length scale and local flame structure in turbulent premixed H2-air flames[C]. The Japanese 38th Symposium on Combustion, 2000. [13] Tanahashi M, Fujimura M, Miyauchi T. Coherent fine-scale eddies in turbulent premixed flames[J]. Proceedings of the Combustion Institute, 2000, 28(1):529-535. doi: 10.1016/S0082-0784(00)80252-0 [14] Lachauxa T, Haltera F, Chauveaua C, et al. Flame front analysis of high-pressure turbulent lean premixed methane-air flames[J]. Proceedings of the Combustion Institute, 2004, 30(1):819-826. https://www.sciencedirect.com/science/article/pii/S0082078404002437 [15] Yuen F T C, Ömer L Gülder. Premixed turbulent flame front structure investigation by Rayleigh scattering in the thin reaction zone regime[J]. Proceedings of the Combustion Institute, 2009, 32(2):1747-1754. doi: 10.1016/j.proci.2008.08.005 [16] Marshall A, Venkateswaran P, Noble D, et al. Development and characterization of a variable turbulence generation system[J]. Experiments in Fluids, 2011, 51(3):611-620. doi: 10.1007/s00348-011-1082-6 [17] Skiba A W, Wabel T, Temme J, et al. Measurements to determine the regimes of turbulent premixed flames[C]. AIAA/SAE/ASEE Joint Propulsion Conference, 2013. [18] Zhang M, Wang J H, Xie Y L, et al. Measurement on instantaneous flame front structure of turbulent premixed CH4/H2/air flames[J]. Experimental Thermal and Fluid Science, 2014, 52(1):288-296. [19] Laws E M, Livesey J L. Flow through screens[J]. Annual Review of Fluid Mechanics, 1978, 10(1):247-266. doi: 10.1146/annurev.fl.10.010178.001335 [20] Mazellier N, Danaila L, Renou B. Multi-scale energy injection:a new tool to generate intense homogeneous and isotropic turbulence for premixed combustion[J]. Journal of Turbulence, 2010, 11(43):1-30. https://core.ac.uk/display/49941649 [21] Driscoll J F. Turbulent premixed combustion:Flamelet structure and its effect on turbulent burning velocities[J]. Progress in Energy and Combustion Science, 2008, 34(1):91-134. doi: 10.1016/j.pecs.2007.04.002 [22] Zhang M, Wang J H, Xie Y L, et al. Flame front structure and burning velocity of turbulent premixed CH4/H2/air flames[J]. International Journal of Hydrogen Energy, 2013, 38(26):11421-11428. doi: 10.1016/j.ijhydene.2013.05.051 [23] Kobayashi H, Hagiwara H, Kaneko H, et al. Effects of CO2 dilution on turbulent premixed flames at high pressure and high temperature[J]. Proceedings of the Combustion Institute, 2007, 31(1):1451-1458. doi: 10.1016/j.proci.2006.07.159 -
点击查看大图
计量
- 文章访问数: 169
- HTML全文浏览量: 62
- PDF下载量: 7
- 被引次数: 0
