燃气轮机柔和燃烧室初步研究
发布时间：2018-07-15 22:53
【摘要】：燃气轮机以其效率高、调峰性能好等优势得到了广泛的应用,是国防和国民经济重要的核心动力设备。燃气轮机燃烧室作为能源转化的核心部件,朝着燃烧室出口温度更高、燃烧效率更高、燃料适应性更强、NOx排放更低的方向发展。而随着燃烧室出口温度的逐步提高和越来越严格的环保要求,NOx排放控制显得尤为关键。柔和燃烧具有峰值火焰温度低、温度场分布均匀、NOx排放低、燃烧稳定性好、燃料适应性强等特点,有发展成为下一代燃气轮机燃烧技术的潜力。为建立应用于燃气轮机的柔和燃烧,通常采用提高反应物入射动量的方式,从而诱导足够烟气回流,降低反应速率,实现容积燃烧。较高的射流动量可以将火焰锋面吹散,减小温度梯度,从而降低NOx生成；高温回流烟气可以预热反应物,燃烧稳定性高；烟气回流和容积燃烧又能延长反应时间,保证较高的燃烧效率。根据上述柔和燃烧实现的指导思想,本文基于某型F级燃气轮机燃烧室额定工况,即燃烧室压力p=16atm,热强度Q=20.5MW/m3-atm,空气温度Ta=723K,燃料为CH4,其温度Tf=288K,参照原有燃烧室几何边界,通过CFD三维模拟,设计并优化适用于实际燃气轮机的柔和燃烧室方案,并开展试验验证。首先完成简化模型燃烧室设计和建模,在当量比φ为0.7的前提下,研究了模型燃烧室中空气顺流/逆流布置、烟气出口直径、空气燃料预混比例、预混入射角等变量以及改变当量比φ对燃烧性能的影响。获得如下结论：该工况下采用空气平行于燃烧室壁面的顺流布置方案更能充分利用燃烧室空间,并获得较大的烟气回流比；改变烟气出口直径对内部流场影响较小；燃烧室最高温度Tmax受当量比φ、反应物掺混性能等多因素影响；预混方式能明显降低燃烧室的最高温度和反应强度,反应区也更弥散。根据上述简化模型燃烧室中的研究结果,结合F级燃烧室接口几何参数,设计并优化适用于实际燃气轮机的柔和燃烧室方案,当量比取φ=0.625,重点研究了单个喷嘴的射流动量对燃烧性能的影响,结果表明：采用预混射流方式,喷嘴个数N取8或者12,射流速度V在80～110m/s之间时,能获得较高的燃烧效率和较低的污染物排放,此时燃烧室压力损失相对较低。为了验证本文的设计方案,保持燃烧室热强度和当量比基本不变,设计加工了1/2缩尺柔和燃烧室,开展了常温常压燃烧试验,结果表明：提高反应物入射速度能明显降低CO和NOx排放；不同热强度下柔和燃烧均能保持清洁燃烧特性；φ=0.6～0.65时,CO排放均不高于12ppm@15%O2, NOx排放低于2ppm@15%O2。初步验证了柔和燃烧室方案的可行性。本文的计算、优化、试验过程及方法可为燃气轮机柔和燃烧室的进一步设计工作提供参考借鉴。
[Abstract]:Gas turbine has been widely used because of its high efficiency and good peak-shaving performance. It is an important core power equipment for national defense and national economy. Gas turbine combustor, as the core component of energy conversion, is developing towards higher outlet temperature, higher combustion efficiency and lower NOx emission. With the gradual increase of combustion chamber outlet temperature and more stringent environmental requirements, NOx emission control is particularly critical. Soft combustion has the characteristics of low peak flame temperature, low NOx emission with uniform temperature distribution, good combustion stability and strong fuel adaptability. It has the potential to develop into the next generation gas turbine combustion technology. In order to establish a soft combustion system for gas turbines, increasing the incident momentum of reactants is usually used to induce enough flue gas reflux, reduce reaction rate and realize volumetric combustion. Higher emitter momentum can blow the flame front away and reduce the temperature gradient, thus reducing no _ x formation; high temperature reflux can preheat reactants and the combustion stability is high; flue gas reflux and volumetric combustion can also prolong the reaction time. Ensure high combustion efficiency. According to the guiding principle of the above mild combustion, this paper is based on the rated working conditions of a certain type of F-grade gas turbine combustor, namely, the combustion chamber pressure p ~ (16) atm, the thermal intensity Q ~ (20. 5) MW / m ~ (3-atm), the air temperature (Tax) 723K, and the fuel (Ch _ 4), the temperature of which is TfN _ (288) K, with reference to the geometry boundary of the original combustion chamber. Through CFD 3D simulation, the soft combustor scheme suitable for actual gas turbine was designed and optimized, and the test was carried out. At first, the design and modeling of the simplified model combustor are completed. Under the premise of the equivalent ratio 蠁 of 0.7, the air downstream / countercurrent arrangement, flue gas outlet diameter and air fuel premixing ratio in the model combustor are studied. The influence of variables such as incident angle of premixing and change of equivalent ratio 蠁 on combustion performance. The conclusions are as follows: under this condition, the downstream arrangement with air parallel to the wall of the combustion chamber can make full use of the combustor space and obtain a larger flue gas reflux ratio, and changing the flue gas outlet diameter has little effect on the internal flow field. The maximum temperature T _ (max) of the combustion chamber is affected by the equivalent ratio 蠁 and the mixing properties of reactants, and the maximum temperature and reaction intensity of the combustion chamber can be obviously reduced by the premixing mode, and the reaction zone is more dispersed. According to the research results of the simplified model combustion chamber and the geometric parameters of the F class combustor interface, the soft combustor scheme suitable for the actual gas turbine is designed and optimized. The effect of jet flow momentum of a single nozzle on combustion performance is studied with the equivalent ratio of 蠁 0.62 5. The results show that when the jet velocity V is between 80~110m/s and the number of nozzles N is 8 or 12, the premixed jet is adopted. Higher combustion efficiency and lower pollutant emission can be obtained, and the pressure loss of combustor is relatively low. In order to verify the design of this paper and keep the thermal intensity and equivalent ratio of combustion chamber basically unchanged, a 1 / 2 scale soft combustor was designed and manufactured, and the combustion test was carried out at room temperature and atmospheric pressure. The results show that increasing the incident rate of reactants can obviously reduce the emission of CO and no _ x, and keep clean combustion characteristics under different thermal intensity, and the emission of CO is not higher than 12ppm @ 15O _ 2 and the emission of no _ x is lower than that of 15O _ 2 at 蠁 _ (0.6) O _ (0.65), and the emission of no _ x is less than 2 ppm @ 15O _ (2). The feasibility of the soft combustor scheme is preliminarily verified. The calculation, optimization, test process and method in this paper can be used for reference for the further design of the gas turbine soft combustor.
【学位授予单位】：中国科学院研究生院(工程热物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK473
本文编号：2125641
[Abstract]:Gas turbine has been widely used because of its high efficiency and good peak-shaving performance. It is an important core power equipment for national defense and national economy. Gas turbine combustor, as the core component of energy conversion, is developing towards higher outlet temperature, higher combustion efficiency and lower NOx emission. With the gradual increase of combustion chamber outlet temperature and more stringent environmental requirements, NOx emission control is particularly critical. Soft combustion has the characteristics of low peak flame temperature, low NOx emission with uniform temperature distribution, good combustion stability and strong fuel adaptability. It has the potential to develop into the next generation gas turbine combustion technology. In order to establish a soft combustion system for gas turbines, increasing the incident momentum of reactants is usually used to induce enough flue gas reflux, reduce reaction rate and realize volumetric combustion. Higher emitter momentum can blow the flame front away and reduce the temperature gradient, thus reducing no _ x formation; high temperature reflux can preheat reactants and the combustion stability is high; flue gas reflux and volumetric combustion can also prolong the reaction time. Ensure high combustion efficiency. According to the guiding principle of the above mild combustion, this paper is based on the rated working conditions of a certain type of F-grade gas turbine combustor, namely, the combustion chamber pressure p ~ (16) atm, the thermal intensity Q ~ (20. 5) MW / m ~ (3-atm), the air temperature (Tax) 723K, and the fuel (Ch _ 4), the temperature of which is TfN _ (288) K, with reference to the geometry boundary of the original combustion chamber. Through CFD 3D simulation, the soft combustor scheme suitable for actual gas turbine was designed and optimized, and the test was carried out. At first, the design and modeling of the simplified model combustor are completed. Under the premise of the equivalent ratio 蠁 of 0.7, the air downstream / countercurrent arrangement, flue gas outlet diameter and air fuel premixing ratio in the model combustor are studied. The influence of variables such as incident angle of premixing and change of equivalent ratio 蠁 on combustion performance. The conclusions are as follows: under this condition, the downstream arrangement with air parallel to the wall of the combustion chamber can make full use of the combustor space and obtain a larger flue gas reflux ratio, and changing the flue gas outlet diameter has little effect on the internal flow field. The maximum temperature T _ (max) of the combustion chamber is affected by the equivalent ratio 蠁 and the mixing properties of reactants, and the maximum temperature and reaction intensity of the combustion chamber can be obviously reduced by the premixing mode, and the reaction zone is more dispersed. According to the research results of the simplified model combustion chamber and the geometric parameters of the F class combustor interface, the soft combustor scheme suitable for the actual gas turbine is designed and optimized. The effect of jet flow momentum of a single nozzle on combustion performance is studied with the equivalent ratio of 蠁 0.62 5. The results show that when the jet velocity V is between 80~110m/s and the number of nozzles N is 8 or 12, the premixed jet is adopted. Higher combustion efficiency and lower pollutant emission can be obtained, and the pressure loss of combustor is relatively low. In order to verify the design of this paper and keep the thermal intensity and equivalent ratio of combustion chamber basically unchanged, a 1 / 2 scale soft combustor was designed and manufactured, and the combustion test was carried out at room temperature and atmospheric pressure. The results show that increasing the incident rate of reactants can obviously reduce the emission of CO and no _ x, and keep clean combustion characteristics under different thermal intensity, and the emission of CO is not higher than 12ppm @ 15O _ 2 and the emission of no _ x is lower than that of 15O _ 2 at 蠁 _ (0.6) O _ (0.65), and the emission of no _ x is less than 2 ppm @ 15O _ (2). The feasibility of the soft combustor scheme is preliminarily verified. The calculation, optimization, test process and method in this paper can be used for reference for the further design of the gas turbine soft combustor.
【学位授予单位】：中国科学院研究生院(工程热物理研究所)
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TK473
【参考文献】
相关期刊论文 前1条
1 米建春;李鹏飞;郑楚光;;环形喷嘴预混无焰燃烧的数值模拟(英文)[J];Chinese Journal of Chemical Engineering;2010年01期
，本文编号：2125641
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