顺序分级柔和燃烧器的实验和数值研究
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摘要
柔和燃烧具有温度场均匀、燃烧噪音低以及低污染排放的优势,这使得其在燃气轮机中有很好的应用前景。针对燃机应用的柔和燃烧主要通过新鲜燃料空气和烟气掺混实现,所以理解新鲜燃气和烟气之间的相互作用对促进柔和燃烧的应用很有意义。另外在柔和燃烧的实现形式中,分级燃烧方式可以方便地提供高温烟气而不需要依靠复杂的结构来回流大量烟气,故以分级方式实现柔和燃烧也有较好的发展前景。而本文设计的串行分级式柔和燃烧器可以同时兼顾这两方面的研究,即一方面研究新鲜预混气和烟气的相互作用对柔和燃烧的影响,另外一方面对柔和燃烧和分级燃烧技术相结合进行初步探索。
本燃烧器利用首段产生轴流高温烟气,并在掺混段采用交叉射流的方式进行新鲜预混气和高温烟气的掺混,然后混合物在柔和燃烧段实现燃烧。根据实验目的不同,实验采用了两种结构形式的燃烧器。其中渐扩型燃烧器主要用于研究不同工况下柔和燃烧的火焰形态以及不同条件下的着火延迟现象。而直筒型燃烧器主要用其研究分段式燃烧器的污染排放性能。实验研究中主要考察四个变量对柔和燃烧的影响,其分别是第一段的质量流量、第一段当量比、第二段质量流量和第二段当量比。
对于渐扩实验器,实验测得了其OH-PLIF图像并结合CFD模拟分析了内部流场、组分场以及温度场,从而研究各个量对火焰特性以及着火延迟的影响。结果显示掺混段掺混性能和燃烧初温对火焰形态和着火延迟影响较大。在其他条件不变的情况下,较好的掺混以及较高的初温都会减小着火延迟距离,并使燃烧区域减小。
实验测得了直筒式燃烧器的CO和NO排放,并结合化学反应网络模型对结果进行分析,其中柔和燃烧段采用柱塞流模型进行简化处理。结果显示NO排放主要受燃烧温度以及在燃烧器内的停留时间影响,在燃烧温度越高、停留时间越长的情况下NO排放越高。由于不考虑散热影响,模拟燃烧温度要高于实际值,而高温下CO2分解造成CO排放值在模拟结果中比实验结果较高。
通过本文研究,对串行分级燃烧器中的柔和燃烧状态、着火延迟距离以及污染排放性能有了较为全面的认识。
Mild combustion is characterized by homogenous temperature field, low combustion noise and low pollution emission. All of these features make mild combustion is promising in being utilized in gas turbine combustor. In present study, mild combustion focusing on gas turbine combustor is mainly achieved by mixing fresh fuel/air with flue gas. Therefore, a better understand of the interaction between fresh fuel/air and flue gas is meaning for promoting the application of mild combustion. Besides of this, among all of the combustor structure used to achieve mild combustion, staged combustion, which can supply flue gas in a convenient way and does not depend on complicated structure to achieve flue gas recirculation, is a promising method. While with the present serial staged combustor both topics mentioned above can be investigated.
First stage of this combustor is used to produce axial flow high temperature flue gas, which is used to assist to achieve mild combustion. In the mixing part, fresh CH4 and air mixture mix with flue gas in the way of crossflow injecting. In the result, mild combustion happens in the second stage. In the experiment, two types second stage, one with divergent part and the other's shape is cylinder, are utilized based on different research purposes. For the one with divergent part, flame structure and phenomena of ignition delay are studied. While cylinder shape second stage is mainly used for investigating the properties of pollution emissions. In the research, four variables, which include first stage equivalence ratio, first stage mass flow rate, second stage equivalence ratio and second stage mass flow rate, are considered.
For combustor with divergent part, OH-PLIF images and CFD simulation are used to analysis the flow field, composition profile and temperature field of second stage. Based on the results, flame characteristics and ignition delay features are investigated. Results show that mixing characteristics and initial temperature are the most important factors. When keeping other parameters unchanged, better mixing and higher initial temperature will make shorter ignition delay time and more intense combustion region.
Pollution emissions, which include NO and CO, of cylinder shape combustor are measured. Together with chemical reaction network simulation, emission properties of the combustor are investigated. In the simulation, the mild stage is simplified to Plug Flow reactor. Results indicate that NO formation mainly influenced by combustion temperature and residence time. Higher combustion temperature and longer residence time will result in more NO formation. While for CO emission, the simulation results are much higher than measurement results. This is because simulation employs adiabatic model and theoretical temperature is much higher than real one. In this condition some CO2 will dissociate to CO, as a result, CO concentration become much higher.
Based on the present study, the flame feature, ignition delay and properties of pollution emission of mild combustion are better understood.
本燃烧器利用首段产生轴流高温烟气,并在掺混段采用交叉射流的方式进行新鲜预混气和高温烟气的掺混,然后混合物在柔和燃烧段实现燃烧。根据实验目的不同,实验采用了两种结构形式的燃烧器。其中渐扩型燃烧器主要用于研究不同工况下柔和燃烧的火焰形态以及不同条件下的着火延迟现象。而直筒型燃烧器主要用其研究分段式燃烧器的污染排放性能。实验研究中主要考察四个变量对柔和燃烧的影响,其分别是第一段的质量流量、第一段当量比、第二段质量流量和第二段当量比。
对于渐扩实验器,实验测得了其OH-PLIF图像并结合CFD模拟分析了内部流场、组分场以及温度场,从而研究各个量对火焰特性以及着火延迟的影响。结果显示掺混段掺混性能和燃烧初温对火焰形态和着火延迟影响较大。在其他条件不变的情况下,较好的掺混以及较高的初温都会减小着火延迟距离,并使燃烧区域减小。
实验测得了直筒式燃烧器的CO和NO排放,并结合化学反应网络模型对结果进行分析,其中柔和燃烧段采用柱塞流模型进行简化处理。结果显示NO排放主要受燃烧温度以及在燃烧器内的停留时间影响,在燃烧温度越高、停留时间越长的情况下NO排放越高。由于不考虑散热影响,模拟燃烧温度要高于实际值,而高温下CO2分解造成CO排放值在模拟结果中比实验结果较高。
通过本文研究,对串行分级燃烧器中的柔和燃烧状态、着火延迟距离以及污染排放性能有了较为全面的认识。
Mild combustion is characterized by homogenous temperature field, low combustion noise and low pollution emission. All of these features make mild combustion is promising in being utilized in gas turbine combustor. In present study, mild combustion focusing on gas turbine combustor is mainly achieved by mixing fresh fuel/air with flue gas. Therefore, a better understand of the interaction between fresh fuel/air and flue gas is meaning for promoting the application of mild combustion. Besides of this, among all of the combustor structure used to achieve mild combustion, staged combustion, which can supply flue gas in a convenient way and does not depend on complicated structure to achieve flue gas recirculation, is a promising method. While with the present serial staged combustor both topics mentioned above can be investigated.
First stage of this combustor is used to produce axial flow high temperature flue gas, which is used to assist to achieve mild combustion. In the mixing part, fresh CH4 and air mixture mix with flue gas in the way of crossflow injecting. In the result, mild combustion happens in the second stage. In the experiment, two types second stage, one with divergent part and the other's shape is cylinder, are utilized based on different research purposes. For the one with divergent part, flame structure and phenomena of ignition delay are studied. While cylinder shape second stage is mainly used for investigating the properties of pollution emissions. In the research, four variables, which include first stage equivalence ratio, first stage mass flow rate, second stage equivalence ratio and second stage mass flow rate, are considered.
For combustor with divergent part, OH-PLIF images and CFD simulation are used to analysis the flow field, composition profile and temperature field of second stage. Based on the results, flame characteristics and ignition delay features are investigated. Results show that mixing characteristics and initial temperature are the most important factors. When keeping other parameters unchanged, better mixing and higher initial temperature will make shorter ignition delay time and more intense combustion region.
Pollution emissions, which include NO and CO, of cylinder shape combustor are measured. Together with chemical reaction network simulation, emission properties of the combustor are investigated. In the simulation, the mild stage is simplified to Plug Flow reactor. Results indicate that NO formation mainly influenced by combustion temperature and residence time. Higher combustion temperature and longer residence time will result in more NO formation. While for CO emission, the simulation results are much higher than measurement results. This is because simulation employs adiabatic model and theoretical temperature is much higher than real one. In this condition some CO2 will dissociate to CO, as a result, CO concentration become much higher.
Based on the present study, the flame feature, ignition delay and properties of pollution emission of mild combustion are better understood.
引文
[1]薛福培.我国工业燃气轮机的现状与前景.全国化工热工设计技术中心站第八届技术委员会成立大会暨2002年大型技术交流会,2002.
[2]Cavaliere, A. and M. De Joannon, Mild combustion. Progress in Energy and Combustion Science,2004.30(4):p.329-366.
[3]Maruta K, Muso K, Takeda K, Niioka T. Reaction zone structure in flameless combustion. Proceeding of Combustion Institute,2000,28:p.2117-23.
[4]Wunning, J.A. and J.G. Wunning, Flameless oxidation to reduce thermal NO-formation. Progress in Energy and Combustion Science,1997.23(1):p.81-94.
[5]Gupta AK. Flame characteristic and challenges with high temperature air combustion. Proceedings of Second International Seminar on High Temperature Combustion in Industrial Furnaces, Jernkontoret-KTH, Stockholm, Sweden,2000.
[6]Oberlack M, A.R., Peters N, On stocastic Damkohler number variations in a homogeneous flow reactor. Combustion Theory and Modelling,2004.4(4):p.495-509.
[7]Katsuki, M. and Hasegawa. Principles and potential of HiCOT combustion. in Proceeding of the Combustion Institute.1998.
[8]Kumar, S., P.J. Paul, and H.S. Mukunda, Studies on a new high-intensity low-emission burner. Proceedings of the Combustion Institute,2002.29(1):p.1131-1137.
[9]周怀春,盛锋,姚洪,高温空气燃烧技术-21世纪关键技术之一.工业炉,1998(1)：p.19-31.关于
[10]Yedidia Neumeier, Yoav Weksler, etc al. Ultra Low Emissions Combustor With Non-Premixed Reactants Injection. AIAA 2005-3775 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July 10-13 2005, Tucson, Arizona.
[11]Mohan K. Bobba, Priya Gopalakrishnan, et al. Flame structure and stabilization mechanisms in stagnation-point reverse-flow combustor. Journal of Engineering for gas turbines and power,2008.130.
[12]M. K. Bobba, P. Gopalakrishnan, et al. Characteristics of combustion processes in a stagnation point reverse flow combustor. Proceeding of GT2006, GT2006-91217.
[13]Israel Institute of Technology. FLOXCOM final report. ENK5-CT-2000-00114[R]. Israel Institute of Technology,2004
[14]Y. Levy, et al. The role of the recirculating gases in the mild combustion regime formation. Proceedings of GT2007. GT2007-27369.
[15]Guoqiang Li, Ephraim J. Gutmark, et al. Experimental Study of a Flameless Gass turbine Combustor. Proceding of GT2006. GT2006-91051.
[16]G. Arvind Rao, et al. Chemical kinetic analysis of a flameless gas turbine combustor. Proceeding of ASME Turbo Expo 2008:Power for land, sea and Air. GT2008-50619.
[17]Erwann Guillou, Michael Cornwell, Ephraim Gutmark. Application of "Flamless" Combustion for gas turbine engines.47th AIAA Aerospace Science Meeting Including The New Horizons Forum and Aerospace Exposition 5-8 January 2009, Orlando, Florida. AIAA 2009-225.
[18]R. Luckerath, W. Meier, and M. Aigner, FLOX(?) combustion at high pressure with different fuel compositions. Journal of Engineering for Gas Turbines and Power,2008. 130(1):p.011505-1-01105-6.
[19]H. Schutz, et al. Analysis of the pollutant formation in the flow(?) combustion. Journal of Engineering for Gas Turbines and Power,2008.130:p.011503-1-01103-9.
[20]Tadashige Kawakami, Naoki Aida, et al. Injection of lean mixtures into hot burned gas for maintaining low-NOx emissions over extended range of fuel-air ratios in prevaporized combustion. Journal of KNOES International Combustion Engine,2003.
[21]Hideshi Yamada, et al. Low-NOx emission over an enlarged range of overall equivalence rations by staged lean premixed tubular flame combustion. Proceedings of GT2005. GT2005-68849.
[22]Masato Hiramatsu, Yoshifumi Nakashima, et al. Combustion characteristics of small size gas turbine combustor fueled with biomass gas employing flameless combustion. GT2007-27636.
[23]Bruckner-Kalb, J.R., et al. Operation characteristics of a premixed sub-PPM NOx burner with periodical recirculation of combustion products. in 51st ASME Turbo Expo.2006. Barcelona, SPAIN:Amer Soc Mechanical Engineers.
[24]Jochen R. Kalb, Thomas Sattelmayer. Lean Blowout limit and NOx production of a premixed sub-ppm NOx burner with periodic recirculation of combustion products. Journal of Engineering for Gas Turbines and Power,2006.128:p.247-254
[25]D. Guyot, et al. Pollutant and Noise Emissions in a Flameless Trapped-Vortex Reheat Burner (FTVRB).43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 8-11 July 2007, Cincinnati, OH. AIAA 2007-5630.
[26]陈钦.燃气轮机燃烧室柔和燃烧条件与特征的研究[D].北京：中国科学院工程热 物理研究所,2010.
[27]吕煊.适用于微小型燃气轮机富氢燃料的无焰燃烧技术[D].北京：中国科学院工程热物理研究所,2010.
[28]http://www.netl.doe.gov/technologies/coalpower/turbines/refshelf/handbook/3.2.1.3.pdf
[29]Davis, L. B. and Black, S. H.. "Dry Low NOx Combustion Systems for GE Heavy-Duty Gas Turbines",2000,GER 3568G.
[30]http://www.escuelaendesa.com/pdf/Alstom.pdf
[31]Leonel O. Arellano, et al. DEVELOPMENT & DEMONSTRATION OF ENGINE READY SURFACE-STABILIZED COMBUSTION SYSTEM, Proceedings of GT2006, GT2006-91285.
[32]Schofield, K. and M. Steinberg. Quantitative atomic and molecular laser fluorescence in the study of detailed combustion process. Optical Engineering,1981.20:p.501-510.
[33]Mark, J.D. and D.R. C.. Two-dimensional imaging of OH laser-induced fluorescence in a flame. Optics Letters,1982.7(8):p.382-384.
[34]Ronaid, K.H., M.S. Jerry, and H.P. Phillip. Planar Laser-Fluorescence Imaging of Combustion Gases. Applied Physics B (Photophysics and Laser Chemistry),1990.50:p. 441-454.
[35]赵建荣,陈立红,俞钢,OH在火焰浓度分布图像及与温度关系的PLIF和CARS研究.分析测试学报,2000.19(6)：p.1-4.
[36]赵建荣,平面激光诱导荧光显示火焰中OH的分布图像.流体测量技术,2000.14(2)：p.67-71.
[37]Beer, J.M. and N.A. Chigier. Combustion Aerodynamics.1983:Robert E. rieger Publishing Company Inc.
[38]Kissel R. Evolution des appareil de mesure etc. Communication at the Third "Journee detudes surles flammes", Paris,1958.
[39]Uhttp://www.me.berkeley.edu/drm/U.
[40]Uhttp://www.me.berkeley.edu/gri_mech/U.
[41]Gupta, A.K., S. Bolz, and T. Hasegawa. Effect of air preheat temperature and oxygen concentration on flame structure and emission. Journal of Energy Resources Technology-Transactions of the Asme,1999.121(3):p.209-216.
[42]Grillo, A., and Slack, M.W.,. Shock Tube Study of Ignition Delay Times in Methane-Oxygen-Nitrogen-Argon Mixtures. Combustion and Flame,1976,27, pp 377-381
[43]Turns, S.R.. An Introduction to Combustion:Concepts and Applications (2nd ed.).2000, Singapore:McGraw-Hill Book Co.
[44]A. Wulff, J. Hourmouziadis. Technology Review of Aeroengine Pollutant Emissions. Aerospace Science and Technology,1997, (8):p.59-98.
[45]C.K. Law, A. Makino and T.F. Lu. On the off-stoichiometric peaking of adiabatic flame temperature. Combustion and Flame,2006, (145):p.808-819.
[46]岑可法,姚强等.高等燃烧学.浙江：浙江大学出版社,2002.
[2]Cavaliere, A. and M. De Joannon, Mild combustion. Progress in Energy and Combustion Science,2004.30(4):p.329-366.
[3]Maruta K, Muso K, Takeda K, Niioka T. Reaction zone structure in flameless combustion. Proceeding of Combustion Institute,2000,28:p.2117-23.
[4]Wunning, J.A. and J.G. Wunning, Flameless oxidation to reduce thermal NO-formation. Progress in Energy and Combustion Science,1997.23(1):p.81-94.
[5]Gupta AK. Flame characteristic and challenges with high temperature air combustion. Proceedings of Second International Seminar on High Temperature Combustion in Industrial Furnaces, Jernkontoret-KTH, Stockholm, Sweden,2000.
[6]Oberlack M, A.R., Peters N, On stocastic Damkohler number variations in a homogeneous flow reactor. Combustion Theory and Modelling,2004.4(4):p.495-509.
[7]Katsuki, M. and Hasegawa. Principles and potential of HiCOT combustion. in Proceeding of the Combustion Institute.1998.
[8]Kumar, S., P.J. Paul, and H.S. Mukunda, Studies on a new high-intensity low-emission burner. Proceedings of the Combustion Institute,2002.29(1):p.1131-1137.
[9]周怀春,盛锋,姚洪,高温空气燃烧技术-21世纪关键技术之一.工业炉,1998(1)：p.19-31.关于
[10]Yedidia Neumeier, Yoav Weksler, etc al. Ultra Low Emissions Combustor With Non-Premixed Reactants Injection. AIAA 2005-3775 41st AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit, July 10-13 2005, Tucson, Arizona.
[11]Mohan K. Bobba, Priya Gopalakrishnan, et al. Flame structure and stabilization mechanisms in stagnation-point reverse-flow combustor. Journal of Engineering for gas turbines and power,2008.130.
[12]M. K. Bobba, P. Gopalakrishnan, et al. Characteristics of combustion processes in a stagnation point reverse flow combustor. Proceeding of GT2006, GT2006-91217.
[13]Israel Institute of Technology. FLOXCOM final report. ENK5-CT-2000-00114[R]. Israel Institute of Technology,2004
[14]Y. Levy, et al. The role of the recirculating gases in the mild combustion regime formation. Proceedings of GT2007. GT2007-27369.
[15]Guoqiang Li, Ephraim J. Gutmark, et al. Experimental Study of a Flameless Gass turbine Combustor. Proceding of GT2006. GT2006-91051.
[16]G. Arvind Rao, et al. Chemical kinetic analysis of a flameless gas turbine combustor. Proceeding of ASME Turbo Expo 2008:Power for land, sea and Air. GT2008-50619.
[17]Erwann Guillou, Michael Cornwell, Ephraim Gutmark. Application of "Flamless" Combustion for gas turbine engines.47th AIAA Aerospace Science Meeting Including The New Horizons Forum and Aerospace Exposition 5-8 January 2009, Orlando, Florida. AIAA 2009-225.
[18]R. Luckerath, W. Meier, and M. Aigner, FLOX(?) combustion at high pressure with different fuel compositions. Journal of Engineering for Gas Turbines and Power,2008. 130(1):p.011505-1-01105-6.
[19]H. Schutz, et al. Analysis of the pollutant formation in the flow(?) combustion. Journal of Engineering for Gas Turbines and Power,2008.130:p.011503-1-01103-9.
[20]Tadashige Kawakami, Naoki Aida, et al. Injection of lean mixtures into hot burned gas for maintaining low-NOx emissions over extended range of fuel-air ratios in prevaporized combustion. Journal of KNOES International Combustion Engine,2003.
[21]Hideshi Yamada, et al. Low-NOx emission over an enlarged range of overall equivalence rations by staged lean premixed tubular flame combustion. Proceedings of GT2005. GT2005-68849.
[22]Masato Hiramatsu, Yoshifumi Nakashima, et al. Combustion characteristics of small size gas turbine combustor fueled with biomass gas employing flameless combustion. GT2007-27636.
[23]Bruckner-Kalb, J.R., et al. Operation characteristics of a premixed sub-PPM NOx burner with periodical recirculation of combustion products. in 51st ASME Turbo Expo.2006. Barcelona, SPAIN:Amer Soc Mechanical Engineers.
[24]Jochen R. Kalb, Thomas Sattelmayer. Lean Blowout limit and NOx production of a premixed sub-ppm NOx burner with periodic recirculation of combustion products. Journal of Engineering for Gas Turbines and Power,2006.128:p.247-254
[25]D. Guyot, et al. Pollutant and Noise Emissions in a Flameless Trapped-Vortex Reheat Burner (FTVRB).43rd AIAA/ASME/SAE/ASEE Joint Propulsion Conference & Exhibit 8-11 July 2007, Cincinnati, OH. AIAA 2007-5630.
[26]陈钦.燃气轮机燃烧室柔和燃烧条件与特征的研究[D].北京：中国科学院工程热 物理研究所,2010.
[27]吕煊.适用于微小型燃气轮机富氢燃料的无焰燃烧技术[D].北京：中国科学院工程热物理研究所,2010.
[28]http://www.netl.doe.gov/technologies/coalpower/turbines/refshelf/handbook/3.2.1.3.pdf
[29]Davis, L. B. and Black, S. H.. "Dry Low NOx Combustion Systems for GE Heavy-Duty Gas Turbines",2000,GER 3568G.
[30]http://www.escuelaendesa.com/pdf/Alstom.pdf
[31]Leonel O. Arellano, et al. DEVELOPMENT & DEMONSTRATION OF ENGINE READY SURFACE-STABILIZED COMBUSTION SYSTEM, Proceedings of GT2006, GT2006-91285.
[32]Schofield, K. and M. Steinberg. Quantitative atomic and molecular laser fluorescence in the study of detailed combustion process. Optical Engineering,1981.20:p.501-510.
[33]Mark, J.D. and D.R. C.. Two-dimensional imaging of OH laser-induced fluorescence in a flame. Optics Letters,1982.7(8):p.382-384.
[34]Ronaid, K.H., M.S. Jerry, and H.P. Phillip. Planar Laser-Fluorescence Imaging of Combustion Gases. Applied Physics B (Photophysics and Laser Chemistry),1990.50:p. 441-454.
[35]赵建荣,陈立红,俞钢,OH在火焰浓度分布图像及与温度关系的PLIF和CARS研究.分析测试学报,2000.19(6)：p.1-4.
[36]赵建荣,平面激光诱导荧光显示火焰中OH的分布图像.流体测量技术,2000.14(2)：p.67-71.
[37]Beer, J.M. and N.A. Chigier. Combustion Aerodynamics.1983:Robert E. rieger Publishing Company Inc.
[38]Kissel R. Evolution des appareil de mesure etc. Communication at the Third "Journee detudes surles flammes", Paris,1958.
[39]Uhttp://www.me.berkeley.edu/drm/U.
[40]Uhttp://www.me.berkeley.edu/gri_mech/U.
[41]Gupta, A.K., S. Bolz, and T. Hasegawa. Effect of air preheat temperature and oxygen concentration on flame structure and emission. Journal of Energy Resources Technology-Transactions of the Asme,1999.121(3):p.209-216.
[42]Grillo, A., and Slack, M.W.,. Shock Tube Study of Ignition Delay Times in Methane-Oxygen-Nitrogen-Argon Mixtures. Combustion and Flame,1976,27, pp 377-381
[43]Turns, S.R.. An Introduction to Combustion:Concepts and Applications (2nd ed.).2000, Singapore:McGraw-Hill Book Co.
[44]A. Wulff, J. Hourmouziadis. Technology Review of Aeroengine Pollutant Emissions. Aerospace Science and Technology,1997, (8):p.59-98.
[45]C.K. Law, A. Makino and T.F. Lu. On the off-stoichiometric peaking of adiabatic flame temperature. Combustion and Flame,2006, (145):p.808-819.
[46]岑可法,姚强等.高等燃烧学.浙江：浙江大学出版社,2002.