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清华大学学报(自然科学版)  2020, Vol. 60 Issue (6): 485-492    DOI: 10.16511/j.cnki.qhdxxb.2020.25.015
  专题:能源领域中的多相流动基础及应用 本期目录 | 过刊浏览 | 高级检索 |
高速圆射流中典型非球形颗粒的扩散特性
黄文仕, 吴玉新, 冯乐乐, 张缦, 张扬
清华大学 能源与动力工程系, 热科学与动力工程教育部重点实验室, 北京 100084
Dispersion characteristics of typical non-spherical particles in a high-speed round jet
HUANG Wenshi, WU Yuxin, FENG Lele, ZHANG Man, ZHANG Yang
Key Laboratory for Thermal Science and Power Engineering of Ministry of Education, Department of Energy and Power Engineering, Tsinghua University, Beijing 100084, China
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摘要 低氧稀释(moderate and intense low-oxygen dilution,MILD)燃烧具有传热均匀、NOx污染物排放低的特点。新一代MILD煤粉燃烧技术主要通过高速射流引起强烈的湍流混合来实现。其中,煤颗粒在高速射流中的扩散行为非常关键。目前对球形颗粒在气固射流中扩散行为的研究已非常深入,然而化石燃料属于典型的非球形颗粒,其在射流中的扩散行为与球形颗粒具有一定的差异,该类非球形颗粒在高速射流下的扩散特性值得进一步研究。为此,该文采用玻璃珠、玻璃渣和煤粉等颗粒开展了宽Re范围下的高速两相圆射流实验,通过激光Doppler相位分析技术(phase-Doppler anemometry,PDA)获取并分析了颗粒的质量浓度、速度及湍动能分布随球形度、粒径以及射流速度的变化规律。结果表明:非球形颗粒在射流中的质量浓度、速度、湍动能分布与粒径较小的球形颗粒具有一定相似性,但其扩散行为不能仅通过Stokes数进行定量表征,除曳力之外,升力对非球形颗粒扩散也具有一定影响;与球形颗粒相比,非球形颗粒的扩散更为显著,其主要原因是其径向湍动能显著增强所致;射流速度的增加促进了颗粒的剪切层集聚和径向扩散,对非球形颗粒的促进作用更强。
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黄文仕
吴玉新
冯乐乐
张缦
张扬
关键词 气固两相流高速射流颗粒扩散球形度    
Abstract:Moderate and intense low-oxygen dilution (MILD) combustion is appealing due to its uniform heat flux profile and low NOx emissions. The new generation of MILD coal combustion burners use high-speed jets with strong turbulent mixing. The dispersion of the coal particles in the high-speed jet is a key issue in such systems. There are many studies of the dispersion of spherical particles in particle-laden jets in the literature. However, the dispersion of fossil fuel particles, which are typically not spherical, differs from that of spherical particles, so the dispersion characteristics of these non-spherical particles in high-speed jets still deserves further study. This study used glass beads, glass powder and pulverized coal as the solid phase in a high-speed two-phase round jet for a wide range of Reynolds numbers. The particle concentrations, velocities and turbulent kinetic energy distributions were measured for various particle sphericities, sizes and jet velocities using laser phase-Doppler anemometry (PDA). The results show that the concentration, velocity and turbulent kinetic energy distribution characteristics of non-spherical particles are similar to those of smaller spherical particles. However, the non-spherical particle dispersion cannot be accurately characterized by just the Stokes number since the lift can strongly affect the particle dispersion. Non-spherical particles are more easily dispersed than spherical particles, mainly due to a significant increase in the radial turbulent kinetic energy. Increasing the jet velocity promotes the shear layer growth and radial dispersion of the particles and more strongly influences the non-spherical particle dispersion than the particle size or sphericity.
Key wordsparticle-laden flow    high-speed jet    particle dispersion    sphericity
收稿日期: 2019-09-23      出版日期: 2020-04-27
基金资助:国家自然科学基金资助项目(51761125011);国家质检总局科技项目(2017QK178-02)
通讯作者: 吴玉新,副教授,E-mail:wuyx09@tsinghua.edu.cn     E-mail: wuyx09@tsinghua.edu.cn
引用本文:   
黄文仕, 吴玉新, 冯乐乐, 张缦, 张扬. 高速圆射流中典型非球形颗粒的扩散特性[J]. 清华大学学报(自然科学版), 2020, 60(6): 485-492.
HUANG Wenshi, WU Yuxin, FENG Lele, ZHANG Man, ZHANG Yang. Dispersion characteristics of typical non-spherical particles in a high-speed round jet. Journal of Tsinghua University(Science and Technology), 2020, 60(6): 485-492.
链接本文:  
http://jst.tsinghuajournals.com/CN/10.16511/j.cnki.qhdxxb.2020.25.015  或          http://jst.tsinghuajournals.com/CN/Y2020/V60/I6/485
  
  
  
  
  
  
  
  
  
  
  
[1] GALLETTI C, PARENTE A, TOGNOTTI L. Numerical and experimental investigation of an MILD combustion burner[J]. Combustion and Flame, 2007, 151(4):649-664.
[2] LI P F, MI J C, DALLY B B, et al. Progress and recent trend in MILD combustion[J]. Science China Technological Sciences, 2011, 54(2):255-269.
[3] ZHANG H, YUE G X, LU J F, et al. Development of high temperature air combustion technology in pulverized fossil fuel fired boilers[J]. Proceedings of the Combustion Institute, 2007, 31(2):2779-2785.
[4] WANG F F, LI P F, MI J C, et al. A refined global reaction mechanism for modeling coal combustion under moderate or intense low-oxygen dilution condition[J]. Energy, 2018, 157:764-777.
[5] AHN S, TANNO K, WATANABE H. Numerical analysis of particle dispersion and combustion characteristics on a piloted coaxial pulverized coal jet flame[J]. Applied Thermal Engineering, 2017, 124:1194-1202.
[6] CHEN Z C, LI Z Q, WANG F Q, et al. Gas/particle flow characteristics of a centrally fuel rich swirl coal combustion burner[J]. Fuel, 2008, 87(10-11):2102-2110.
[7] 崔金雷, 王希麟, 容易. 颗粒在气固两相圆湍射流近场截面对气相的影响[J]. 清华大学学报(自然科学版), 2005, 45(8):1088-1090. CUI J L, WANG X L, RONG Y. Particle effect on the gas phase in a near field cross section in gas-solid round turbulent jets[J]. Journal of Tsinghua University (Science and Technology), 2005, 45(8):1088-1090. (in Chinese)
[8] 燕小芬, 王希麟. 不同材料颗粒对两相湍射流场的调制规律[J]. 清华大学学报(自然科学版), 2007, 47(8):1375-1379. YAN X F, WANG X L. Effect of different material particle on the modulation of two-phase turbulent jets[J]. Journal of Tsinghua University (Science and Technology), 2007, 47(8):1375-1379. (in Chinese)
[9] FLECKHAUS D, HISHIDA K, MAEDA M. Effect of laden solid particles on the turbulent flow structure of a round free jet[J]. Experiments in Fluids, 1987, 5(5):323-333.
[10] 罗坤, 樊建人, 郑水华, 等. 圆湍射流中的拟序结构和颗粒弥散[J]. 化工学报, 2006, 57(6):1329-1333. LUO K, FAN J R, ZHENG S H, et al. Coherent structures and particle dispersion in a turbulent round jet[J]. CIESC Journal, 2006, 57(6):1329-1333. (in Chinese)
[11] 崔金雷, 王希麟, 容易. 气固两相圆湍射流颗粒对气相流动的影响[J]. 工程热物理学报, 2005, 26(6):974-976. CUI J L, WANG X L, RONG Y. Influence of the dispersed phase on the gas phase in gas-particle turbulent jets[J]. Journal of Engineering Thermophysics, 2005, 26(6):974-976. (in Chinese)
[12] 白建基, 郑水华, 樊建人, 等. Reynolds数对气固两相圆湍射流影响的实验研究[J]. 浙江大学学报(工学报), 2006, 40(3):433-437. BAI J J, ZHENG S H, FAN J R, et al. Experiment study on effects of Reynolds number on gas-particle turbulent round jet[J]. Journal of Zhejiang University (Engineering Science), 2006, 40(3):433-437. (in Chinese)
[13] LAU T C W, NATHAN G J. The effect of Stokes number on particle velocity and concentration distributions in a well-characterised, turbulent, co-flowing two-phase jet[J]. Journal of Fluid Mechanics, 2016, 809:72-110.
[14] 周华辉, 许建良, 李伟锋, 等. 稠密气固两相同轴射流颗粒弥散特性[J]. 化工学报, 2009, 60(2):332-337. ZHOU H H, XU J L, LI W F, et al. Particle dispersion characteristics of dense gas-solids two-phase coaxial jets[J]. CIESC Journal, 2009, 60(2):332-337. (in Chinese)
[15] ZHANG W, TAINAKA K, AHN S, et al. Experimental and numerical investigation of effects of particle shape and size distribution on particles' dispersion in a coaxial jet flow[J]. Advanced Powder Technology, 2018, 29(10):2322-2330.
[16] 由长福, 祁海鹰, 徐旭常. 气固两相流动中非球形颗粒所受曳力的数值研究[J]. 化工学报, 2003, 54(2):188-191. YOU C F, QI H Y, XU X C. Numerical simulation of drag force on non-spherical particle in gas-particle two-phase flow[J]. CIESC Journal, 2003, 54(2):188-191. (in Chinese)
[17] HARTMAN M, TRNKA O, SVOBODA K. Free settling of nonspherical particles[J]. Industrial & Engineering Chemistry Research, 1994, 33(8):1979-1983.
[18] KNOLL M, GERHARDTER H, PRIELER R, et al. Particle classification and drag coefficients of irregularly-shaped combustion residues with various size and shape[J]. Powder Technology, 2019, 345:405-414.
[19] NJOBUENWU D O, FAIRWEATHER M. Dynamics of single, non-spherical ellipsoidal particles in a turbulent channel flow[J]. Chemical Engineering Science, 2015, 123:265-282.
[20] HÅKANSSON K M O, KVICK M, LUNDELL F, et al. Measurement of width and intensity of particle streaks in turbulent flows[J]. Experiments in Fluids, 2013, 54(6):1555.
[21] 冯乐乐, 王景玉, 吴玉新, 等. 颗粒特性对撞击分离器性能影响的实验与数值研究[J]. 化工学报, 2018, 69(8):3348-3355. FENG L L, WANG J Y, WU Y X, et al. Experimental and numerical investigation on effect of particle characteristics on performance of plate-type impact separator[J]. CIESC Journal, 2018, 69(8):3348-3355. (in Chinese)
[22] 邱建荣, 马毓义. 用PDA测量两相湍流流场时固体粒子的选择[J]. 气动实验与测量控制, 1994, 8(1):54-59. QIU J R, MA Y Y. Choice of solid particles during measuring gas-solid two-phase turbulent flow field with particle dynamic analyzer[J]. Aerodynamic Experiment and Measurement & Control, 1994, 8(1):54-59. (in Chinese)
[23] 刘虎. PDA接收方式和参数对气固两相流场测量影响的研究[D]. 哈尔滨:哈尔滨工业大学, 2006. LIU H. Study on the influences of the reception mode and parameters of PDA on the measure of gas-solid flow field[D]. Harbin:Harbin Institute of Technology, 2006. (in Chinese)
[24] BACHALO W D, HOUSER M J. Phase/Doppler spray analyzer for simultaneous measurements of drop size and velocity distributions[J]. Optical Engineering, 1984, 23(5):583-590.
[25] CROWE C T, GORE R A, TROUTT T R. Particle dispersion by coherent structures in free shear flows[J]. Particulate Science and Technology, 1985, 3(3-4):149-158.
[26] 王兵, 张会强, 王希麟, 等. 湍流分离流动中的颗粒弥散机制[J]. 清华大学学报(自然科学版), 2003, 43(11):1507-1510. WANG B, ZHANG H Q, WANG X L, et al. Particle dispersion mechanism in turbulent separated flow[J]. Journal of Tsinghua University (Science and Technology), 2003, 43(11):1507-1510. (in Chinese)
[27] HAIDER A, LEVENSPIEL O. Drag coefficient and terminal velocity of spherical and nonspherical particles[J]. Powder Technology, 1989, 58(1):63-70.
[28] LAU T C W, NATHAN G J. Influence of Stokes number on the velocity and concentration distributions in particle-laden jets[J]. Journal of Fluid Mechanics, 2014, 757(6):432-457.
[29] LEE BLACK D, MCQUAY M Q. Laser-based particle measurements of spherical and nonspherical particles[J]. International Journal of Multiphase Flow, 2001, 27(8):1333-1362.
[30] ZHANG W, WATANABE H, KITAGAWA T. Numerical investigation of effects of particle shape on dispersion in an isotropic turbulent flow[J]. Advanced Powder Technology, 2018, 29(9):2048-2060.
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