RQL燃烧室燃烧特性的数值研究
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摘要
由于环境的日益恶化,低污染燃烧技术受到越来越多的关注,尤其要降低NOX的排放。RQL燃烧技术是基于NOX生成理论研究的基础上对燃烧进行分级燃烧,将燃烧室分为低NOX生成的富油燃烧区和贫油燃烧区,中间采用高速射流进行快速掺混的淬熄区实现由富油燃烧向贫油燃烧的快速转换。以实现燃料能够稳定燃烧的同时降低NOX排放的目标。
本文采用CFD数值模拟方法对RQL模型燃烧室内气动力学特性、燃烧特性以及污染物的排放进行了数值研究。对三种不同强度旋流数计算结果进行对比分析表明,中等旋流强度能够满足空气与燃料适度混合,且能避免富油区壁面承受过高温度。通过冷态流场的分析,淬熄段流型的合理分布可通过调整流量分配来实现快速混合淬熄。对于给定的流量分配,当量比从1变化到1.6七种工况,对其温度场和污染物排放进行了数值研究,结果表明：RQL燃烧室温升增大的同时出口温度分布系数降低,NOX的排放量先降低再增大,出口CO和碳黑的排放随当量比的增大而增加。当量比1.4时,出口温度达到1620k,能够满足涡轮入口温度的要求。在此当量比基础上研究了四种不同流量分配下燃烧室温场和污染物排放的变化规律,增大淬熄空气流量,出口最高温度和出口温度分布系数均明显降低,燃烧室出口NOX、CO和碳黑的排放平均浓度均下降,掺混效果增强,但射流深度较小,为此对模型燃烧室进行修改,去掉冷却射流环带,与同条件下的工况相比较,淬熄深度加深,掺混加强,出口温度分布系数降低,具有更低NOX、CO和碳黑排放浓度,实现了RQL燃烧室的设计目标。
本文的研究结果表明所设计的RQL模型燃烧室既满足出口品质要求又能有效降低NOX污染物排放。该研究结果对航空发动机新概念燃烧室的设计与分析具有较大参考价值。
Due to the environment deteriorating increasingly, more and more attention are paid to the low pollution combustion, especially to low NOx emission combustion. RQL technology utilizes staged burning based on the theoretic study of formation oxides of nitrogen(NOx). The combustor is divided into Rich-burn zone, Lean-burn zone which produce less NOx. The transition, called Quick-quench zone, from fuel-rich to fuel-lean combustion is obtained through a rapid mixing of the rich mixture with dilution air jets. The aim is to combust stably and produce less amounts of NOX.
In this paper, CFD numerical simulation method has been applied to study aerodynamic characteristic, combustion characteristic and pollutant emission of the RQL model combustor. Through comparative analysis of three different kinds of swirl number, medium intensity of swirl could not only ensure appropriate mixing of air and fuel, but also avoid high temperature on Rich zone wall. The reasonable distribution of flow patterns in Quench sector may be adjusted by the air jet distribution to achieve the rapid quenching and mixing through the analysis of cold flow field. When equivalence ratio varies from 1 to 1.6 with the constant flow-distribution,the study of temperature field and pollutant emissions showed that temperature rised of RQL combustor increases while output temperature-distribution coefficient decreased, and NOx emission lowered first then increased, meanwhile CO emission and soot emission increased with equivalence ratio rising. When equivalence ratio is 1.4, output temperature can reach 1620k,which meets the temperature demand of the flow to turbine. Under this circumstance, the results of temperature field and pollutant emission with 4 different flow distribution along the combustor chamber showed that output supreme temperature and temperature-distribution coefficient decreased as increasing the jet flow mass, meanwhile mass-weighted average of output NOx emission, CO emission and soot emission lowered. Tough large amount of jet flow mass can mix more effectively, the penetration depth is comparatively small. So the model combustor must be modified, getting rid of the annular impinging jet. Comparing to the run with the impinging, cooling annular jet, this run had a deeper penetration and a more effective mixing. In addition, output temperature distribution coefficient decrease along with lower emission of NOx, CO and soot, which achieved the design goal.
The simulation results and analyses demonstrated that RQL model combustor could meet the requirements of both output temperature quality and reducing NOx emission. This study has considerable reference to the design and analysis of new concept combustor in aero engine.
本文采用CFD数值模拟方法对RQL模型燃烧室内气动力学特性、燃烧特性以及污染物的排放进行了数值研究。对三种不同强度旋流数计算结果进行对比分析表明,中等旋流强度能够满足空气与燃料适度混合,且能避免富油区壁面承受过高温度。通过冷态流场的分析,淬熄段流型的合理分布可通过调整流量分配来实现快速混合淬熄。对于给定的流量分配,当量比从1变化到1.6七种工况,对其温度场和污染物排放进行了数值研究,结果表明：RQL燃烧室温升增大的同时出口温度分布系数降低,NOX的排放量先降低再增大,出口CO和碳黑的排放随当量比的增大而增加。当量比1.4时,出口温度达到1620k,能够满足涡轮入口温度的要求。在此当量比基础上研究了四种不同流量分配下燃烧室温场和污染物排放的变化规律,增大淬熄空气流量,出口最高温度和出口温度分布系数均明显降低,燃烧室出口NOX、CO和碳黑的排放平均浓度均下降,掺混效果增强,但射流深度较小,为此对模型燃烧室进行修改,去掉冷却射流环带,与同条件下的工况相比较,淬熄深度加深,掺混加强,出口温度分布系数降低,具有更低NOX、CO和碳黑排放浓度,实现了RQL燃烧室的设计目标。
本文的研究结果表明所设计的RQL模型燃烧室既满足出口品质要求又能有效降低NOX污染物排放。该研究结果对航空发动机新概念燃烧室的设计与分析具有较大参考价值。
Due to the environment deteriorating increasingly, more and more attention are paid to the low pollution combustion, especially to low NOx emission combustion. RQL technology utilizes staged burning based on the theoretic study of formation oxides of nitrogen(NOx). The combustor is divided into Rich-burn zone, Lean-burn zone which produce less NOx. The transition, called Quick-quench zone, from fuel-rich to fuel-lean combustion is obtained through a rapid mixing of the rich mixture with dilution air jets. The aim is to combust stably and produce less amounts of NOX.
In this paper, CFD numerical simulation method has been applied to study aerodynamic characteristic, combustion characteristic and pollutant emission of the RQL model combustor. Through comparative analysis of three different kinds of swirl number, medium intensity of swirl could not only ensure appropriate mixing of air and fuel, but also avoid high temperature on Rich zone wall. The reasonable distribution of flow patterns in Quench sector may be adjusted by the air jet distribution to achieve the rapid quenching and mixing through the analysis of cold flow field. When equivalence ratio varies from 1 to 1.6 with the constant flow-distribution,the study of temperature field and pollutant emissions showed that temperature rised of RQL combustor increases while output temperature-distribution coefficient decreased, and NOx emission lowered first then increased, meanwhile CO emission and soot emission increased with equivalence ratio rising. When equivalence ratio is 1.4, output temperature can reach 1620k,which meets the temperature demand of the flow to turbine. Under this circumstance, the results of temperature field and pollutant emission with 4 different flow distribution along the combustor chamber showed that output supreme temperature and temperature-distribution coefficient decreased as increasing the jet flow mass, meanwhile mass-weighted average of output NOx emission, CO emission and soot emission lowered. Tough large amount of jet flow mass can mix more effectively, the penetration depth is comparatively small. So the model combustor must be modified, getting rid of the annular impinging jet. Comparing to the run with the impinging, cooling annular jet, this run had a deeper penetration and a more effective mixing. In addition, output temperature distribution coefficient decrease along with lower emission of NOx, CO and soot, which achieved the design goal.
The simulation results and analyses demonstrated that RQL model combustor could meet the requirements of both output temperature quality and reducing NOx emission. This study has considerable reference to the design and analysis of new concept combustor in aero engine.
引文
[1]林宇震,许全宏,刘高恩.燃气轮机燃烧室[M],北京：国防工业出版社,2008
[2]侯晓春,季鹤鸣等.高性能航空燃气轮机燃烧技术[M],北京：国防工业出版社,2002
[3]Novik A S, et al.Multifuel Evalution of Rich/Quench/Lean Combustor. ASME 83-GT-140
[4]Scott Samuelsen. The Gas Turbine Handbook [M], U. S. Department of Energy, Office of Fossil Energy, National Energy Technology Laboratory,2006
[5]M.V.Talpallikar,C.E. Smith, M. C.Lai, J. D. Holdeman. CFD Analysis of Jet Mixing in Low NOx Flametube Combustors[R], ASME-91-GT-217,1991
[6]A. s. Feitelberg, M. A. Lacey. The GE Rich-Quench-Lean Gas Turbine Combustor [J], Journal of Engineering for Gas Turbines Power,1998,120[3]:502-508
[7]O. Diers,J. Koopman, M. Fischer, C. Hassa. Investigation of Two Advanced Cooling Mixing Concepts for a Rich Quench Lean Combustor [J], Journal of Engineering for Gas Turbines Power,2002,124[4]:784-791
[8]James D. Holdema, Clarence T. Chang. The Effects of Air Preheat and Number of Orifices on Flow and Emissions in an RQL Mixing Section[J], Journal of Fluids Engineering,2007, 129[11]:1460-1467
[9]M. Sc. Aryoso Nirmolo. Optimization of Radial Jets Mixing in.Cross-flow of Combustion Chambers using Computational Fluid Dynamics[D], Ottovon-Guericke-University,2006
[10]P. Anacleto, M. V. Heitor, A. L. N. Moreira. The mean and turbulent flowfields in a model RQL gas-turbine combustor[J], Experiments in Fluids,1996,22:153-164
[11]航空发动机设计手册总编委会编.航空发动机设计手册第9册[M],北京：航空工业出版社2000
[12]傅德薰,马延文.计算流体力学[M],北京：高等教育出版社,2001
[13]周立行.湍流两相流动与燃烧的理论与数值模拟[M],北京：科学出版社,1994
[14]范维澄等.计算燃烧学[M],合肥：安徽科学出版社,1987
[15]赵坚行.燃烧的数值模拟[M],北京：科学出版社,2002
[16]金如山.航空燃气轮机燃烧室[M].北京：宇航出版社,1988
[17]May Y. Leong, Vincent G. McDonell, G. Scott Samuelsen. Mixing of an Airblast-Atomized Fuel Spray Injected Into a Crossflow of Air[R], NASA CR-2000-210467
[18]Dr Edward J. Mularz and Dr Daniel L. Bulzan. Spray Combustion Experiments and Numerical Predictions, Vehicle Propulsion Directorate, U. S. Army Research Laboratory, NASA; University of Toledo
[19]Lille S, Dobski T and Blasiak W. Visualisation of fuel jet in conditions of highly preheated air combustion[J], AIAA Journal of Propulsion and Power 2000;16(4):595-600
[20]J R Tilston, M I Wedlock and A D Marchment. The Influence of Air Distribution on Homogeneity and Pollutant Formation in the Primary Zone of a Tubular Combustor, AGARD, May 1993
[21]L. Li, T. Liu, X. F. Peng. Flow characteristics in an annular burner with fully film cooling[J], Applied Thermal Engineering 25 (2005) 3013-3024
[22]L. Selle, L. Benoit. Joint use of compressible large-eddy simulation and Helmholtz solvers for the analysis of rotating modes in an industrial swirled burner[J], Combustion and Flame 145 (2006) 194-205
[23]Mustafa Ilbas. The effect of thermal radiation and radiation models on hydrogen-hydrocarbon combustion modeling [R], International Journal of Hydrogen Energy 30 (2005) 1113-1126
[24]B. Zamuner, P. Gilbank. Numerical simulation of the reactive two-phase flow in a kerosene/air tubular combustor[J], Aerospace Science and Technology 6 (2002) 521-529
[25]L. Li, X. F. Peng, T. Liu. Combustion and cooling performance in an aero-engine [J], annular combustor Applied Thermal Engineering 26 (2006) 1771-1779
[26]Jong-Hoon Park, Sang-Soon Hwang, Youngbin Yoon, etal.Effect of swirl cup on characteristics of fuel spray in gasturbine combustors[R]. AIAA 2000-3352.
[27]Rizk N K, Mongia H C. Semi-analytical fuel injector performance correlation approach[R]. AIAA-89-2902,1989
[28]Rizk N K, Mongia H C. Further validation of a semi-analytical approach for fuel injectors of different concepts[R]. AIAA-90-2190,1990
[29]Mongia H C, Vermeersch M, Thomsen D, et al. A simple reactorbased approach for correlating lean blowout of turbopropulsion engine combustors[R]. AIAA 2001-3420, 2001
[30]J.O. Hinze. Turbulence. McGraw-Hill, NewYork,1975
[31]Ateshkadi A, McDonell V G, Samuelsen GS. Effect of mixer geometry on fuel spray distribution, emission and stability[R]. AIAA-98-0247,1998
[32]Mongia H C, AI2Roub M, Danis A, et al. Swirl cup modeling:part1 [R]. AIAA 2001-3576, 2001
[33]Park J H, Yoon Y, Jeung I S. Effect of swirl cup on characteristics of fuel spray in gas turbine combustors [R]. AIAA 20002-3352,2000
[34]黄勇,郭志辉.某燃烧室头部旋流油雾场特性的实验研究[C].中国航空学会第五届动力年会.北京：中国航空学会动力专业分会,5：103-110,2003
[35]朗洪俭,郭志辉,黄勇.主燃孔对旋流杯下游流场的影响[J].推进技术,2006,27(2)：110-113
[36]徐华胜,黄义勇.喷嘴特性对双涡流器头部气动雾化效果的影响[A].中国航空学会第五届动力年会,燃烧分册[C].2003：134-140
[37]刘大响.航空发动机技术的发展和建议[J].中国工程科学,1999,1(2)：24-29
[38]周强.世界军用航空动力技术的现状与展望.长沙航空职业技术学院学报[J],2003,3(1)：26-30
[39]胡晓煜.航空发动机技术发展展望[J],航空制造技术,2004(10)：50～54
[40]宋双文.中小型航空发动机燃烧室技术的进展[J],国际航空,2004(10)：56～58
[41]K.-Y. Hsu,C. Carter. Fuel Distribution About a Cavity Flameholder in Surpersonic Flow[J].AIAA-2000-358.36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 17-19 July,2000 Huntsville, Alabama
[42]M. R. Gruber, R. A. Baurle. Fundamental Studies of Cavity-Based Flameholder Concepts for Supersonic Combustors [J]. AIAA 99-2248.35th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 20-24 June 1999, Los Angeles, California
[43]Kyung Moo Kim,Seung Wook Baek. Numerical study on supersonic combustion with cavity-based fuel injection. International Journal of Heat and Mass Transfer[J].VOL.47,2004:271～286
[44]Faure J. Malo-Molina, Datta V. Gaitonde, et al. Numerical Investigation of a 3-D Chemically Reacting Scramjet Engine at High Altitudes Using JP8-Air Mixtures[J]. AIAA-2005-1435.43rd AIAA Aerospace Sciences Meeting and Exhibit 10-13 January2005, Reno, Nevada
[45]张均勇,张宝诚.航空发动机燃烧室工作稳定性的研究[J].航空发动机,第一期,2001
[46]陶文铨编著.数值传热学[M].西安交通大学出版社,2001.5
[47]蔡锐彬,卢振雄.燃烧污染与环境保持[M].广州：华南理工大学出版社,1998
[48]刘刚,李黎.喷嘴特性对燃烧室内烟粒浓度和火焰辐射的影响[J].航空学报,1994,15,(6)
[49]傅德燕主编.流体力学数值模拟[M].北京：国防工业出版社,1993
[50]章梓雄,董曾男.粘性流体力学[M].北京：清华大学出版社,1998
[2]侯晓春,季鹤鸣等.高性能航空燃气轮机燃烧技术[M],北京：国防工业出版社,2002
[3]Novik A S, et al.Multifuel Evalution of Rich/Quench/Lean Combustor. ASME 83-GT-140
[4]Scott Samuelsen. The Gas Turbine Handbook [M], U. S. Department of Energy, Office of Fossil Energy, National Energy Technology Laboratory,2006
[5]M.V.Talpallikar,C.E. Smith, M. C.Lai, J. D. Holdeman. CFD Analysis of Jet Mixing in Low NOx Flametube Combustors[R], ASME-91-GT-217,1991
[6]A. s. Feitelberg, M. A. Lacey. The GE Rich-Quench-Lean Gas Turbine Combustor [J], Journal of Engineering for Gas Turbines Power,1998,120[3]:502-508
[7]O. Diers,J. Koopman, M. Fischer, C. Hassa. Investigation of Two Advanced Cooling Mixing Concepts for a Rich Quench Lean Combustor [J], Journal of Engineering for Gas Turbines Power,2002,124[4]:784-791
[8]James D. Holdema, Clarence T. Chang. The Effects of Air Preheat and Number of Orifices on Flow and Emissions in an RQL Mixing Section[J], Journal of Fluids Engineering,2007, 129[11]:1460-1467
[9]M. Sc. Aryoso Nirmolo. Optimization of Radial Jets Mixing in.Cross-flow of Combustion Chambers using Computational Fluid Dynamics[D], Ottovon-Guericke-University,2006
[10]P. Anacleto, M. V. Heitor, A. L. N. Moreira. The mean and turbulent flowfields in a model RQL gas-turbine combustor[J], Experiments in Fluids,1996,22:153-164
[11]航空发动机设计手册总编委会编.航空发动机设计手册第9册[M],北京：航空工业出版社2000
[12]傅德薰,马延文.计算流体力学[M],北京：高等教育出版社,2001
[13]周立行.湍流两相流动与燃烧的理论与数值模拟[M],北京：科学出版社,1994
[14]范维澄等.计算燃烧学[M],合肥：安徽科学出版社,1987
[15]赵坚行.燃烧的数值模拟[M],北京：科学出版社,2002
[16]金如山.航空燃气轮机燃烧室[M].北京：宇航出版社,1988
[17]May Y. Leong, Vincent G. McDonell, G. Scott Samuelsen. Mixing of an Airblast-Atomized Fuel Spray Injected Into a Crossflow of Air[R], NASA CR-2000-210467
[18]Dr Edward J. Mularz and Dr Daniel L. Bulzan. Spray Combustion Experiments and Numerical Predictions, Vehicle Propulsion Directorate, U. S. Army Research Laboratory, NASA; University of Toledo
[19]Lille S, Dobski T and Blasiak W. Visualisation of fuel jet in conditions of highly preheated air combustion[J], AIAA Journal of Propulsion and Power 2000;16(4):595-600
[20]J R Tilston, M I Wedlock and A D Marchment. The Influence of Air Distribution on Homogeneity and Pollutant Formation in the Primary Zone of a Tubular Combustor, AGARD, May 1993
[21]L. Li, T. Liu, X. F. Peng. Flow characteristics in an annular burner with fully film cooling[J], Applied Thermal Engineering 25 (2005) 3013-3024
[22]L. Selle, L. Benoit. Joint use of compressible large-eddy simulation and Helmholtz solvers for the analysis of rotating modes in an industrial swirled burner[J], Combustion and Flame 145 (2006) 194-205
[23]Mustafa Ilbas. The effect of thermal radiation and radiation models on hydrogen-hydrocarbon combustion modeling [R], International Journal of Hydrogen Energy 30 (2005) 1113-1126
[24]B. Zamuner, P. Gilbank. Numerical simulation of the reactive two-phase flow in a kerosene/air tubular combustor[J], Aerospace Science and Technology 6 (2002) 521-529
[25]L. Li, X. F. Peng, T. Liu. Combustion and cooling performance in an aero-engine [J], annular combustor Applied Thermal Engineering 26 (2006) 1771-1779
[26]Jong-Hoon Park, Sang-Soon Hwang, Youngbin Yoon, etal.Effect of swirl cup on characteristics of fuel spray in gasturbine combustors[R]. AIAA 2000-3352.
[27]Rizk N K, Mongia H C. Semi-analytical fuel injector performance correlation approach[R]. AIAA-89-2902,1989
[28]Rizk N K, Mongia H C. Further validation of a semi-analytical approach for fuel injectors of different concepts[R]. AIAA-90-2190,1990
[29]Mongia H C, Vermeersch M, Thomsen D, et al. A simple reactorbased approach for correlating lean blowout of turbopropulsion engine combustors[R]. AIAA 2001-3420, 2001
[30]J.O. Hinze. Turbulence. McGraw-Hill, NewYork,1975
[31]Ateshkadi A, McDonell V G, Samuelsen GS. Effect of mixer geometry on fuel spray distribution, emission and stability[R]. AIAA-98-0247,1998
[32]Mongia H C, AI2Roub M, Danis A, et al. Swirl cup modeling:part1 [R]. AIAA 2001-3576, 2001
[33]Park J H, Yoon Y, Jeung I S. Effect of swirl cup on characteristics of fuel spray in gas turbine combustors [R]. AIAA 20002-3352,2000
[34]黄勇,郭志辉.某燃烧室头部旋流油雾场特性的实验研究[C].中国航空学会第五届动力年会.北京：中国航空学会动力专业分会,5：103-110,2003
[35]朗洪俭,郭志辉,黄勇.主燃孔对旋流杯下游流场的影响[J].推进技术,2006,27(2)：110-113
[36]徐华胜,黄义勇.喷嘴特性对双涡流器头部气动雾化效果的影响[A].中国航空学会第五届动力年会,燃烧分册[C].2003：134-140
[37]刘大响.航空发动机技术的发展和建议[J].中国工程科学,1999,1(2)：24-29
[38]周强.世界军用航空动力技术的现状与展望.长沙航空职业技术学院学报[J],2003,3(1)：26-30
[39]胡晓煜.航空发动机技术发展展望[J],航空制造技术,2004(10)：50～54
[40]宋双文.中小型航空发动机燃烧室技术的进展[J],国际航空,2004(10)：56～58
[41]K.-Y. Hsu,C. Carter. Fuel Distribution About a Cavity Flameholder in Surpersonic Flow[J].AIAA-2000-358.36th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 17-19 July,2000 Huntsville, Alabama
[42]M. R. Gruber, R. A. Baurle. Fundamental Studies of Cavity-Based Flameholder Concepts for Supersonic Combustors [J]. AIAA 99-2248.35th AIAA/ASME/SAE/ASEE Joint Propulsion Conference and Exhibit 20-24 June 1999, Los Angeles, California
[43]Kyung Moo Kim,Seung Wook Baek. Numerical study on supersonic combustion with cavity-based fuel injection. International Journal of Heat and Mass Transfer[J].VOL.47,2004:271～286
[44]Faure J. Malo-Molina, Datta V. Gaitonde, et al. Numerical Investigation of a 3-D Chemically Reacting Scramjet Engine at High Altitudes Using JP8-Air Mixtures[J]. AIAA-2005-1435.43rd AIAA Aerospace Sciences Meeting and Exhibit 10-13 January2005, Reno, Nevada
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