您的当前位置:首页正文

气流特征对水平长管内石松子粉尘爆炸火焰结构的影响

来源:个人技术集锦
第35卷第3期 爆炸与冲击 Vo1.35。No.3 Mav,2015 2015年5月 EXPLOSION AND SHOCK WAVES 气流特征对水平长管内石松子粉尘爆炸 火焰结构的影响 高 伟 ,阿部俊太郎 ,荣建忠。,土桥律。 (1_大连理工大学化工机械学院,辽宁大连116024; 2.东京大学工学院化学系统工程专攻,东京113—8656 3.公安部四川消防研究所,四川成都610036) 摘要:为探索气流特征对水平长管内粉尘爆炸火焰结构的影响,对采用加压送气传输方式形成的石松子 粉尘云经静电引燃后其火焰在水平长管内的传播特性进行实验。利用热线风速仪测量不同气流条件下沿管 径方向的速度分布和湍流强度分布,采用高速摄像系统记录了火焰在水平管道内的传播过程。实验观察到, 即使管内石松子粉尘质量分数相同,仍然会出现2种不同类型的火焰结构:一种类型火焰轮廓规则、清晰,火 焰中心为连续的黄色发光区并由红色边缘火焰包裹;另一种类型火焰空间离散,火焰发光区局部存在,散乱地 呈现不规则状态。详细分析不同气流条件对火焰结构的影响。 关键词:爆炸力学;粉尘爆炸;气动传输;气流特征;火焰结构;火焰传播速度 中图分类号:0383;X932 国标学科代码:13035 文献标志码:A 由于在垂直管道内形成悬浮的粉尘云比在水平管道内要容易得多,因此不少粉尘火焰的研究工作 是在垂直管道内进行的口 ]。在实验室条件下,要实现粉尘火焰在水平长管中的传播与加速,困难主要 在于,因地引力作用很难维持粉尘云在燃烧过程中仍能均匀地悬浮在L/D>>10的水平管内。T.Mat— suda_7_s 在内径4.2 cm、长13 m的水平长管内对采用弱点火能点火的软木和ABC树脂粉尘的火焰传 播特性及气流速度对其最小点火能的影响开展了实验研究。J.H.Pickles[9 提出了包含湍流混合效应 的理论模型,对水平长管内粉尘火焰传播的机理进行了讨论与分析。刘晓利等口 “]设计了内径 158 mm、长23 m的水平粉尘爆轰管,但在其实验研究中只运行了其中的10 m,其长径比L/D仅为63。 陈志华等m。。 在内径140 mm,长为12 m的水平粉尘火焰加速管内,对铝粉悬浮云中火焰加速诱导激 波现象进行了实验研究。白春华等口 在内径300 mm,长71 ITI的水平管道内,对玉米淀粉、小麦粉等有 机粮食粉尘“二次爆炸”过程进行了实验研究,得到了“二次爆炸”发展过程及爆轰波特性。钟圣俊等 采用算子分裂法和FCT格式,数值模拟了水平长管道中的煤粉爆炸。薄涛 。]在水平长管内对粉尘的 爆炸进行了分析,确定了影响粉尘爆炸的因素,这些因素包括粉尘粒度、粉尘质量分数、粉尘湿度、挥发 物含量、惰性粉尘含量以及延迟点火时间等。对于水平管道内粉尘爆炸火焰传播机理的实验数据较少, 且较为分散,缺乏系统研究。本文中利用热线风速仪对水平管道内的气流速度及分布进行测量,采用高 速摄影系统记录火焰在水平长管内的传播过程,详细分析了不同气流条件对火焰传播速度、涡旋结构、 出现条件和相对燃烧速度的影响,可为相关研究提供参考。 1 实验装置及条件 1.1 实验装置 实验装置如图1所示,主要由水平燃烧长管、送风机、时间控制器、粉尘供给装置、多孔板、点火装置 *收稿日期:20l3 O7 08;修回日期:2014—06—03 基金项目:国家自然科学基金项目(51406023);中国博士后科学基金项目(2014M560213) 第一作者:高伟(1984 ),男,博士,讲师,gaowei07@mail.ustc.edu.cn。 378 er,2003:1 156. 爆 炸 与 冲 击 第35卷  R,Mogi T,et a1.Effects of particle characteristics on flame propagation behavior during organic [2] Gao W,Dobashidust explosions in a half-closed chamber[J].Journal of Loss Prevention in the Process Industries,2012,25(6):993— 999. ma M,Matsuda T,et a1.Behavior of flames propagating through lycopodium dust clouds in a ver— [3] Han O S,Yashitieal duct[J].Journal of Loss Prevention in the Process Industries,2000,13(6):449—457. oust C.A few fundamental aspects about ignition and flame propagation in dust clouds[J].Journal of Loss Pre— [4] Prvention in the Process Industries,2006,19(2/3):104—120. [5] Wang S F,Pu Y K,Jia F.An experimental study oil flame propagation in cornstarch dust clouds[J].Combustion Science and Technology,2006,178(10/11):1957—1975. [6] Dobashi R,Senda K.Detailed analysis of flame propagation during dust explosions by UV band observations[J]. Journal of Loss Prevention in the Process Industries,2006,19(2/3):149—153. suda T.The effect of air velocity OD minimum ignition energy for flowing dust—air mixtures in a tube[R].Re— [7] Matsearch Report of the Research Institute of Industrial Safety,RIIS-RR一86,1986. [8] Matsuda T.Flame propagation characteristics of flowing dust—air mixtures in a tube[R].Research Report of the Research Institute of Industrial Safety。RII RR一87,1987. ckles J H.A model for coal dust duct explosions[J].Combustion and Flame,1982,44(1/2/3):153—168. [9] Pi[1O] 刘晓利,李鸿志,叶经方,等.铝粉一空气混和物的爆轰管研究[J].弹道学报,1993(2):76—82. Liu Xiao—li,Li Hong—zhi,Ye Jing—fang,et a1.Detonation tube studies of aluminum powder-air mixture[J].Jour— nal of Ballistics,1993(2):76—82. [11] 刘晓利,李鸿志,郭建国,等.铝粉~空气混和物燃烧转爆轰(DDT)过程的实验研究[J].爆炸与冲击,1995,15(3): 217-228. Liu Xiao—li,Li Hong—zhi,Guo Jian-guo,et a1.An experimental investigation of deflagration to detonation transi— tion(DDT)in aluminum dust-air mixture[J].Explosion and Shock Waves,1995,15(3):217—228. [12] 陈志华,范宝春,刘庆明,等.大型管中两相爆炸现象的实验研究[J].流体力学实验与测量,1998,12(1):44—49. Chen Zhi—hua,Fan Bao—chun,Liu Qing—ruing,et a1.Experimental study on the phenomenon of two phase explo— sion in a large scale tube[J].Experiments and Measurements in Fluid Mechanics,1998,12(1):44—49. [13] 陈志华,范宝春,李鸿志.燃烧管内悬浮铝粉燃烧爆炸过程的研究_J].高压物理学报,2006,20(2):157—162. Chen Zhi—hua,Fan Bao—chun,Li Hong—zhi,et a1.Investigations on combustion and explosion process of suspen— ded aluminum particles in a large combustion tube[J].Chinese Journal of High Pressure Physics,2006,2O(2): 157—162. [14] 白春华,Li Y C,Kauffman C W.工业粉尘“二次爆炸”过程研究[J].中国安全科学学报,1995,5(1):6-11. Bai Chun-hua,Li Y C,Kauffman C W.The explosion behaviour of layered industrial dusts[J].China Safety Sci— ence Journal,1995,5(1):6-11. [15] 钟圣俊,邓煦帆.有机粉尘爆炸的数值模拟[J].中国粉体技术,2000(6):239—243. Zhong Sheng~jun,Deng Xu—fan.Simulation of organic dust explosions[J].China Powder Science and Technology, 2000(6):239—243. [16]薄涛.水平管道爆炸装置中粉尘爆炸特性研究[J].山西化工,2008,28(5):14—16. Bo Tao.The experimental study of dust explosion in horizontal pipeline type exploder[J].Shanxi Chemical Indus try,2008,28(5):14—16. [17] IEI本粉尘工业技术协会粉尘爆炸委员会编.粉尘爆炸火灾对策[M].Ohmsha出版局,2006:21—55. [18] Zhen G,Leuckel W.Determination of dust—dispersion—induced turbulence and its influence on dust explosions[J]. Combustion Science and Technology,1996,113(1):629—639. [19] Hinze J 0.Turbulence[M].2nd ed.Mcgraw-Hill College,1975:27—63.  T,Dobashi R.Effects of particle thermal characteristics on flame structures during dust explosions [2O] Gao W,Mogiof three long—chain monobasic alcohols in an open—space chamber[J].Fuel,2013,l13:86—96. 第3期 高伟,等:气流特征对水平长管内石松子粉尘爆炸火焰结构的影响 379 Effect of airflow characteristics on flame structure for following lycopodium dust—air mixtures in a long horizontal tube Gao Wei 一,Abe Shuntaro。,Rong Jian—zhong。,Dobashi Ritsu (1_School of Chem ical Machinery,Dalian University of Technology, Dalian 116024,Liaoning,China; 2.Department of Chemical System Engineering School of Engineering, University of Tokyo,Tokyo 113—8656,Japan; 3.Sichuan Fire Research Institute of Ministry of Public Security, Chengdu 610036,Sichuan,China) Abstract:Experiments were conducted to investigate the effect of conveying airflow characteristics on flame structure for the electric spark ignition in air flow of lycopodium dust.Hot wire anemometers were used to measure the distributions of velocity and turbulent intensity along the diameter in a 6 cm diameter and 4 m length horizontal acrylic tube of a blow—type pneumatic conveying system.The measured dust—air mixtures flowing velocities ranged between 10 and 30 m/s.A high—speed video camera was utilized to record the flame propagation process and to obtain the direct light emission photographs.Two apparently different types of flames appeared in the flame propagation process un— der different airflow conditions.Type A flame was characterized by a regular and continuous structure with the yellow light..emitting zone in the center surrounding by the red luminous zone.Type B flame was discrete in the space and the structure of the luminous zone was irregular.Furthermore,the flame propagation velocities,vortex structures,formation conditions and relative burning velocities of the tWO types flames under different airflow velocities were discussed in detail. Key words:mechanics of explosion;dust explosion;pneumatic transportation;air flow characteris— tics;flame structure;flame propagation velocity (责任编辑王易难) 

因篇幅问题不能全部显示,请点此查看更多更全内容