冲击射流火焰流场的LDV实验研究
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摘要
搭建了基于激光多普勒测速仪(LDV)的冲击射流火焰流场实验平台,开发了固态粒子发生器、粒子回收装置和精密位移机构等装置,对单孔喷嘴(功率200W)、同轴喷嘴(功率1200W)的自由射流火焰流场和冲击射流火焰流场进行高精度测量,测量数据具有较高的准确性和可重复性。在冲击射流模式下,利用多个位置点的平均速度分量测量值进行流场重构,获得了冲击射流火焰流场基本特征。实验发现:在靠近冲击壁面区域距中心滞止点约1倍喷嘴直径处出现水平方向速度峰值,该点处可能会形成短冲击距离下换热强度的第二次峰值。在同轴射流工况中,外环同轴射流和中心射流间存在一个内部剪切混合层:在自由射流火焰模式下,该混合层随着射流的发展而耗散;在冲击射流火焰模式下,由于受到滞止区的作用,混合层向外扩张。
A Laser Doppler Velocimetry system containing aparticle generator,aparticle collector and a motorized precision translation stage is built to diagnose the fluid fields of a vertical flow burner.The free jet flame and impinging jet flame are investigated,both for a single nozzle(200 W power)and a coaxial dual-nozzle(1200 W power).An adaptable signal to noise ratio(SNR)threshold is analyzed and employed for post-processing.The experimental data shows high repeatability and accuracy in multiple measurements.For impinging jet cases,the Reynolds numbers(Re)of low power and high power flame are 1200 and 7200,respectively.The mean velocity vectors and contours are sketched from the measurements at different axial and radial positions,displaying the main characteristics of the impinging jet flame.Meanwhile,apeak of the horizontal velocity occurs roughly at one-nozzle-diameter distance departed from the nozzle axis in the near-wall region.This feature possibly provides an explanation for the mechanism of the secondary peak of the heat transfer captured in previous literatures.For the cases of coaxial jet,a mixing region exists between the outer annular jet and the core jet:the mixing zone is gradually damped with the development of the free jet flame,whereas radially expanding in the impinging flame driven by the high-pressure stagnation region.
A Laser Doppler Velocimetry system containing aparticle generator,aparticle collector and a motorized precision translation stage is built to diagnose the fluid fields of a vertical flow burner.The free jet flame and impinging jet flame are investigated,both for a single nozzle(200 W power)and a coaxial dual-nozzle(1200 W power).An adaptable signal to noise ratio(SNR)threshold is analyzed and employed for post-processing.The experimental data shows high repeatability and accuracy in multiple measurements.For impinging jet cases,the Reynolds numbers(Re)of low power and high power flame are 1200 and 7200,respectively.The mean velocity vectors and contours are sketched from the measurements at different axial and radial positions,displaying the main characteristics of the impinging jet flame.Meanwhile,apeak of the horizontal velocity occurs roughly at one-nozzle-diameter distance departed from the nozzle axis in the near-wall region.This feature possibly provides an explanation for the mechanism of the secondary peak of the heat transfer captured in previous literatures.For the cases of coaxial jet,a mixing region exists between the outer annular jet and the core jet:the mixing zone is gradually damped with the development of the free jet flame,whereas radially expanding in the impinging flame driven by the high-pressure stagnation region.
引文
[1]Kadam A R,Tajik A R,Hindasageri V.Heat transfer distribution of impinging flame and air jets-A comparative study[J].Applied Thermal Engineering,2016,92:42-49.
[2]Chander S,Ray A.An experimental and numerical study of stagnation point heat transfer for methane/air laminar flame impinging on a flat surface[J].International Journal of Heat and Mass Transfer,2008,51(13-14):3595-3607.
[3]Remie M J,Cremers M F G,Schreel K R A M.Analysis of the heat transfer of an impinging laminar flame jet[J].International Journal of Heat and Mass Transfer,2007,50(13-14):2816-2827.
[4]Chander S,Ray A.Flame impingement heat transfer:A review[J].Energy Conversion and Management,2005,46(18):2803-2837.
[5]徐惊雷,徐忠,肖敏,等.冲击射流的研究概述[J].力学与实践,1999,21(6):8-17.Xu J L,Xu Z,Xiao M,et al.On impinging jet research[J].Mechanics in Engineering,1999,21(6):8-17.
[6]Zuckerman N,Lior N.Jet impingement heat transfer:physics,correlations,and numerical modeling[J].Advances in Heat Transfer,2006,39(06):565-631.
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[8]张建辉,尹航,陈永辰.冲击射流预混火焰的数值模拟[J].能源研究与信息,2011,27(1):38-45.Zhang J H,Dai R,Chen Y C.Numerical simulation of the impinging-jet premixed flame[J].Energy Research and Information,2011,27(1):38-45.
[9]陈庆光,徐忠,张永建.湍流冲击射流流动与传热的数值研究进展[J].力学进展,2002,32(1):92-108.Chen Q G,Xu Z,Zhang Y J.Advances in numerical studies of turbulent impinging jet flow and heat transfer[J].Advances in Mechanics,2002,32(1):92-108.
[10]苑达,王丙兴,王昭东,等.单喷嘴冲击射流的数值模拟[J].中国冶金,2014,24(增刊):222-226.Yuan D,Wang B X,Wang Z D,et al.Numerical simulation of single nozzle jet for ultra-fast cooling[J].China Metallurgy,2014,24(s):222-226.
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[12]熊霏,姚朝晖,郝鹏飞,等.冲击射流的PIV实验研究[J].流体力学实验与测量,2004,18(3):68-72.Xiong F,Yao Z H,Hao P F,et al.PIV investigation of impinging jet[J].Experiments and Measurements in Fluid Mechanics.2004,18(3):68-72.
[13]陈庆光,徐忠,吴玉林,等.矩形管湍流冲击射流场的PIV实验研究[J].实验流体力学,2005,19(1):87-93.Chen Q G,Xu Z,Wu Y L,et al.Experimental study on rectangular turbulent impinging jet flow field by PIV technique[J].Journal of Experiments in Fluid Mechanics,2005,19(1):87-93.
[14]姚朝晖,侯修洲,郝鹏飞.超声速冲击射流的PIV实验研究[J].实验流体力学,2007,21(4):32-35.Yao Z H,Hou X Z,Hao P F.PIV experimental research on supersonic impinging jet[J].Journal of Experiments in Fluid Mechanics,2007,21(4):32-35.
[15]Milson A,Chigier N A.Studies of methane and methane-air flames impinging on a cold plate[J].Combustion and Flame,1973,21(3):295-305.
[16]Van der Meer T H.Stagnation point heat transfer from turbulent low reynolds number jets and flame jets[J].Experimental Thermal and Fluid Science,1991,4(1):115-126.
[17]Chander S,Ray A.Experimental and numerical study on the occurrence of off-stagnation peak in heat flux for laminar methane/air flame impinging on a flat surface[J].International Journal of Heat and Mass Transfer,2011,54(5-6):1179-1186.
[18]Li H B,Zhen H S,Leung C W.Effects of plate temperature on heat transfer and emissions of impinging flames[J].International Journal of Heat and Mass Transfer,2010,53(19-20):4176-4184.
[19]Li H B,Zhen H S,Leung C W.Nozzle effect on heat transfer and CO emission of impinging premixed flames[J].International Journal of Heat and Mass Transfer,2011,54(1-3):625-635.
[20]O’Donovan T S,Murray D B.Jet impingement heat transferPart I:Mean and root-mean-square heat transfer and velocity distributions[J].International Journal of Heat and Mass Transfer,2007,50(17-18):3291-3301.
[21]O’Donovan T S,Murray D B.Jet impingement heat transferPart II:A temporal investigation of heat transfer and local fluid velocities[J].International Journal of Heat and Mass Transfer,2007,50(17-18):3302-3314.
[22]Goldstein R J,Timmers J F.Visualization of heat transfer from arrays of impinging jets[J].International Journal of Heat and Mass Transfer,1982,25(12):1857-1868.
[23]O’Donovan T S.Fluid flow and heat transfer of an impinging air jet[D].Dublin,Ireland:University of Dublin,2005.
[24]Chen Y C,Peters N,Schneemann G A,et al.The detailed flame structure of highly stretched turbulent premixed methane-air flames[J].Combustion and Flame,1996,107(3):223-244.
[25]Zhou B,Brackmann C,Li Q,Wang Z,et al.Distributed reactions in highly turbulent premixed methane/air flames.Part I.Flame structure characterization[J].Combustion and Flame,2014,162(7):2937-2953.
[26]陆嘉,廖光煊,陶常法.甲烷射流扩散火焰结构试验研究[J].安全与环境学报,2010,10(6):164-168.Lu J,Liao G X,Tao C F,Experimental study of flame shape of methane jet diffusion flame[J].Journal of Safety and Environment,2010,10(6):164-168.
[27]Dong L L,Cheung C S,Leung C W.Heat transfer characteristics of an impinging inverse diffusion flame jet-Part I:Free flame structure[J].International Journal of Heat and Mass Transfer,2007,50(25-26):5108-5123.
[28]Dong L L,Cheung C S,Leung C W.Heat transfer characteristics of an impinging inverse diffusion flame jet-Part II:Impinging flame structure and impingement heat transfer[J].International Journal of Heat and Mass Transfer,2007,50(25-26):5124-5138.
[29]Buresti G,Talamelli A,Petagna P.Experimental characterization of the velocity field of a coaxial jet configuration[J].ExperimentalThermal and Fluid Science,1994,9(2):135-146.
[30]令狐昌鸿,王高峰,钟亮,等.旋流流化床固体粒子发生器:中国,201610646669.7[P].2016-11-23.Linhu C H,Wang G F,Zhong L,et al.Swirling fluidized bed solid particle generator:China,201610646669.7[P].2016-11-23.
[31]沈熊.激光测速技术(LDV)诞生50周年启示[J].实验流体力学,2014,28(6):51-55.Shen X.A historical review for the 50th anniversary of laser doppler velocimetry[J].Journal of Experiments in Fluid Mechanics,2014,28(6):51-55.
[32]费业泰.误差理论与数据处理[M].第7版.北京:机械工业出版社,2015.Fei Y T.Error theory and data processing[M].7th ed.Beijing:China Machine Press,2015.
[2]Chander S,Ray A.An experimental and numerical study of stagnation point heat transfer for methane/air laminar flame impinging on a flat surface[J].International Journal of Heat and Mass Transfer,2008,51(13-14):3595-3607.
[3]Remie M J,Cremers M F G,Schreel K R A M.Analysis of the heat transfer of an impinging laminar flame jet[J].International Journal of Heat and Mass Transfer,2007,50(13-14):2816-2827.
[4]Chander S,Ray A.Flame impingement heat transfer:A review[J].Energy Conversion and Management,2005,46(18):2803-2837.
[5]徐惊雷,徐忠,肖敏,等.冲击射流的研究概述[J].力学与实践,1999,21(6):8-17.Xu J L,Xu Z,Xiao M,et al.On impinging jet research[J].Mechanics in Engineering,1999,21(6):8-17.
[6]Zuckerman N,Lior N.Jet impingement heat transfer:physics,correlations,and numerical modeling[J].Advances in Heat Transfer,2006,39(06):565-631.
[7]过增元.场协同原理与强化传热新技术[M].北京:中国电力出版社,2004.Guo Z Y.Field synergy principle and enhanced heat transfer technology[M].Beijing:China Electric Power Press,2004.
[8]张建辉,尹航,陈永辰.冲击射流预混火焰的数值模拟[J].能源研究与信息,2011,27(1):38-45.Zhang J H,Dai R,Chen Y C.Numerical simulation of the impinging-jet premixed flame[J].Energy Research and Information,2011,27(1):38-45.
[9]陈庆光,徐忠,张永建.湍流冲击射流流动与传热的数值研究进展[J].力学进展,2002,32(1):92-108.Chen Q G,Xu Z,Zhang Y J.Advances in numerical studies of turbulent impinging jet flow and heat transfer[J].Advances in Mechanics,2002,32(1):92-108.
[10]苑达,王丙兴,王昭东,等.单喷嘴冲击射流的数值模拟[J].中国冶金,2014,24(增刊):222-226.Yuan D,Wang B X,Wang Z D,et al.Numerical simulation of single nozzle jet for ultra-fast cooling[J].China Metallurgy,2014,24(s):222-226.
[11]徐惊雷,徐忠,张堃元,等.雷诺数对半封闭紊流冲击射流流场影响的实验研究[J].南京航空航天大学学报,2001,33(2):187-190.Xu J L,Xu Z,Zhang K Y,et al.Experimental study of Reynolds number effect on turbulent impinging jet flow[J].Journal of Nanjing University of Aeronautics and Astronautics,2001,33(2):187-190.
[12]熊霏,姚朝晖,郝鹏飞,等.冲击射流的PIV实验研究[J].流体力学实验与测量,2004,18(3):68-72.Xiong F,Yao Z H,Hao P F,et al.PIV investigation of impinging jet[J].Experiments and Measurements in Fluid Mechanics.2004,18(3):68-72.
[13]陈庆光,徐忠,吴玉林,等.矩形管湍流冲击射流场的PIV实验研究[J].实验流体力学,2005,19(1):87-93.Chen Q G,Xu Z,Wu Y L,et al.Experimental study on rectangular turbulent impinging jet flow field by PIV technique[J].Journal of Experiments in Fluid Mechanics,2005,19(1):87-93.
[14]姚朝晖,侯修洲,郝鹏飞.超声速冲击射流的PIV实验研究[J].实验流体力学,2007,21(4):32-35.Yao Z H,Hou X Z,Hao P F.PIV experimental research on supersonic impinging jet[J].Journal of Experiments in Fluid Mechanics,2007,21(4):32-35.
[15]Milson A,Chigier N A.Studies of methane and methane-air flames impinging on a cold plate[J].Combustion and Flame,1973,21(3):295-305.
[16]Van der Meer T H.Stagnation point heat transfer from turbulent low reynolds number jets and flame jets[J].Experimental Thermal and Fluid Science,1991,4(1):115-126.
[17]Chander S,Ray A.Experimental and numerical study on the occurrence of off-stagnation peak in heat flux for laminar methane/air flame impinging on a flat surface[J].International Journal of Heat and Mass Transfer,2011,54(5-6):1179-1186.
[18]Li H B,Zhen H S,Leung C W.Effects of plate temperature on heat transfer and emissions of impinging flames[J].International Journal of Heat and Mass Transfer,2010,53(19-20):4176-4184.
[19]Li H B,Zhen H S,Leung C W.Nozzle effect on heat transfer and CO emission of impinging premixed flames[J].International Journal of Heat and Mass Transfer,2011,54(1-3):625-635.
[20]O’Donovan T S,Murray D B.Jet impingement heat transferPart I:Mean and root-mean-square heat transfer and velocity distributions[J].International Journal of Heat and Mass Transfer,2007,50(17-18):3291-3301.
[21]O’Donovan T S,Murray D B.Jet impingement heat transferPart II:A temporal investigation of heat transfer and local fluid velocities[J].International Journal of Heat and Mass Transfer,2007,50(17-18):3302-3314.
[22]Goldstein R J,Timmers J F.Visualization of heat transfer from arrays of impinging jets[J].International Journal of Heat and Mass Transfer,1982,25(12):1857-1868.
[23]O’Donovan T S.Fluid flow and heat transfer of an impinging air jet[D].Dublin,Ireland:University of Dublin,2005.
[24]Chen Y C,Peters N,Schneemann G A,et al.The detailed flame structure of highly stretched turbulent premixed methane-air flames[J].Combustion and Flame,1996,107(3):223-244.
[25]Zhou B,Brackmann C,Li Q,Wang Z,et al.Distributed reactions in highly turbulent premixed methane/air flames.Part I.Flame structure characterization[J].Combustion and Flame,2014,162(7):2937-2953.
[26]陆嘉,廖光煊,陶常法.甲烷射流扩散火焰结构试验研究[J].安全与环境学报,2010,10(6):164-168.Lu J,Liao G X,Tao C F,Experimental study of flame shape of methane jet diffusion flame[J].Journal of Safety and Environment,2010,10(6):164-168.
[27]Dong L L,Cheung C S,Leung C W.Heat transfer characteristics of an impinging inverse diffusion flame jet-Part I:Free flame structure[J].International Journal of Heat and Mass Transfer,2007,50(25-26):5108-5123.
[28]Dong L L,Cheung C S,Leung C W.Heat transfer characteristics of an impinging inverse diffusion flame jet-Part II:Impinging flame structure and impingement heat transfer[J].International Journal of Heat and Mass Transfer,2007,50(25-26):5124-5138.
[29]Buresti G,Talamelli A,Petagna P.Experimental characterization of the velocity field of a coaxial jet configuration[J].ExperimentalThermal and Fluid Science,1994,9(2):135-146.
[30]令狐昌鸿,王高峰,钟亮,等.旋流流化床固体粒子发生器:中国,201610646669.7[P].2016-11-23.Linhu C H,Wang G F,Zhong L,et al.Swirling fluidized bed solid particle generator:China,201610646669.7[P].2016-11-23.
[31]沈熊.激光测速技术(LDV)诞生50周年启示[J].实验流体力学,2014,28(6):51-55.Shen X.A historical review for the 50th anniversary of laser doppler velocimetry[J].Journal of Experiments in Fluid Mechanics,2014,28(6):51-55.
[32]费业泰.误差理论与数据处理[M].第7版.北京:机械工业出版社,2015.Fei Y T.Error theory and data processing[M].7th ed.Beijing:China Machine Press,2015.