【作者】 汪凤山；

【导师】 徐建中； 孔文俊；

【作者基本信息】 中国科学院研究生院（工程热物理研究所） ， 工程热物理， 2009， 博士

【摘要】 近年来，随着分布式供能系统的发展，微型燃气轮机在我国得到了高度重视。燃烧室是微型燃气轮机的核心部件，高效低污染燃烧室是发动机排放性能先进性的体现。本学位论文的工作以国家863项目为依托，研究了100kW级微型燃气轮机低NOx排放燃烧室的设计方法，并对其流动、燃烧特性及NOx排放特性进行了数值模拟和实验研究。主要内容如下：1．研究了100kW级微型燃气轮机的低NOx燃烧室设计方法，该设计方法的特点是采用燃料径向分级、值班火炬稳燃、主燃料贫预混燃烧方式。这种设计在保持燃烧室稳定运行的基础上，增大了燃烧室头部空气量，降低了燃烧室高温区的火焰峰值温度，大大降低了燃烧室的NOx排放。2．采用三维计算流体力学设计方法，对影响燃烧室性能及NOx排放的重要结构参数和运行参数进行了研究。揭示了进口温度、主燃区进气旋流强度、值班区进气旋流强度以及主燃区和值班区燃料配比对燃烧室流动、燃烧特性以及NOx排放性能的影响规律。研究发现，总压恢复系数随燃烧室进气温度的升高呈线性降低趋势，即进气从300K提高到873K，燃烧室冷态总压恢复系数从97．5％降到93．3％，影响十分显著；随着主燃区进气旋流强度的增加，燃烧室火焰峰值温度有所降低，燃烧室NOx排放浓度也显著降低。可见，适当提高燃烧室主燃区进气旋流强度有利于降低燃烧室NOx的排放；值班区进气旋流强度对燃烧室温度场影响不大，但当值班区旋流强度增加到一定程度时，值班区通道出口贴近内壁处速度较低，预混气流容易在该处形成回火，从而可能威胁到燃气轮机机组的安全性；燃料配比实验表明，随着值班区燃料量占总燃料量的比例增大，其NOx排放浓度急剧增加，影响十分显著。3．采用三维计算流体力学方法对所设计的燃烧室进行了全尺寸数值分析，并根据数值结果对燃烧室的性能进行评估得到，设计燃烧室总压恢复系数达到93．3％，燃烧室出口NOx排放浓度约为15ppmv。4．建立了微型燃气轮机燃烧室实验台平台，对100kW级设计燃烧室的点火性能、燃烧室在额定工况下的燃烧特性以及部分变工况特性进行了常压模化实验研究。实验结果表明，所设计的100kW燃烧室点火可靠、燃烧效率为99．8％，总压恢复系数为92．2％，NOx排放为9ppmv，CO排放为16ppmv。通过实验结果与数值模拟结果的比较，发现二者在变化趋势上是一致，但具体数值上还有一定差别，这也说明燃烧流场模拟的复杂性，同时，实验和数值模拟结果的比较也表明本文数值模拟结果从工程应用角度看还是可行的。更多还原

【Abstract】 In recent years, with the quickly development of the distributed energy systems, microgas turbine has been received great attentions in China. The combustion chamber is one ofthe core components of the micro gas turbine. It is a manifestation of an advanced enginewith the combustion chamber of high efficient and low emissions. The thesis supported bythe national 863 project studied the design methods for a low NOx emissions combustionchamber of a 100kW grade microturbine. Its flow, combustion characteristics and NOxemissions were investigated numerically and experimentally. The main contents of thedissertation are as follows:1. The design methods of the low NOx emissions combustor were developed. Theoutlet of the methods is that the combustor is a two-stage premixed combustor designedfor use with natural gas fuel. The piloting flame severiced as the duty torch to stable thelean premixed flame. The primary premixed passageway is concentric about the pilotpremixed passageway, which operatered at lean premixed mode. The features of thedesign are the increase of the dome air volume fraction and the decrease of the flame zonepeak temperature while maintaining stable operation of the combustion chamber. As aresult, the NOx emissions were greatly reduced.2. Effects of structural and operating parameters on combustion performances andNOx emissions were investigated by using the 3-D CFD methods. The variation trendsdescribed the influences of the inlet temperature, the primary flow swirling intensity, thepilot flow swirling intensity, as well as the fuel ratio of the main passageway to the pilotpassageway on the combustor’s flow, combustion and NOx emissions. The results showthat, with the increase of the inlet temperature, the total pressure recovery coefficientdeceased linearly. For example, when the inlet air temperature increased from 300K to873K, the total pressure recovery coefficient decreased from 97.5% to 93.3%. With the increase of the primary inlet swirling intensity, the peak flame temperature decreased. TheNOx emission is also decreased significantly. That is to say, the increase of the primaryinlet swirling intensiy was benefited to decrease the NOx emission of the combustor. Thevariations of the pilot inlet swirling intensities were unimportance for the temperatureprofiles and NOx emissions. But when the pilot inlet swirling intensity increased a certaindegree, the flashback maybe observed, which could cause safety threat of the combustor.The fuel allocating experiments showed that NOx emissions sharply increased with theincrease of the pilot fuel fraction.3. Numerical simulations were completed for the designed combustor with 3-Dfull-scale model. According to the results, the performances of this combustor wereevaluated. It is shown that the total pressure recovery coefficient was 93.3%, and the NOxemission of the combustor was 15ppmv.4. An experimental setup for the micro gas turbine combustion chamber wasestablished. Experimental investigations were completed to study the performances of thereference the 100kW combustor. The experimental results indicated that 100kW designedcombustor was ignition flexible, high combustion efficiency of 99.8%, medial totalpressure recovery factor of 92.2%, low NOx emission of 9ppmv and low CO emission of16ppmv. By comparison of the experimental results with the numerical results, they havethe identical variation trends, although the data are different. This is because of thecomplex of the combustion simulations. However, the results showed that the numericalmethods used in this thesis are feasible from the perspective of engineering application.更多还原