数值模拟在合成气燃气轮机燃烧室设计中的应用

采用数值模拟方法对设计燃料为天然气和柴油的某型号燃气轮机燃烧室进行了改造,使其能够高效洁净地燃烧中热值的合成气。数值计算采用了涡团耗散湍流燃烧模型、可实现k-ε湍流模型和离散坐标系辐射模型,SIMPLE压力速度耦合算法以及二阶精度迎风插值格式。对原型燃烧室进行了数值模拟研究,分析了合成气燃料的性质,对比了燃烧天然气和合成气2种燃料时燃烧室入口参数,由此确定了燃烧室改造原则。依照改造原则对原型燃烧室进行了改造,并根据数值模拟的结果对改造方案进行了多次改进,最终得到了合适的改造方案。改造过程说明:对原先燃烧天然气的燃烧室改烧中热值合成气,基本可以不改变火焰筒的结构;燃料喷射孔的面积可以按照与原型喷嘴的燃料喷射速度相同的原则确定,但需要增加旋流器的旋流数。

Application of Numerical Simulation in the Design of Gas Turbine Combustor for Burning Syngas

Numerical simulation was used to retrofit a gas turbine combustor with diesel oil and natural gas as fuel in order to burning medium-heating-value syngas efficiently and clearly. The eddy-dissipation turbulent combustion model, realizable k-e turbulent model, discrete ordinates radiation model, SIMPLE pressure-velocity coupling method and second-order upwind discretization scheme were adopted in the numerical simulation. Based on the numerical simulation research on the original combustor, analysis of the properties of the syngas and the comparison of the combustor inlet parameters for burning natural gas and syngas, the retrofitting principles were determined. Then the original combustor was retrofitted according to the principles and the retrofitting schemes were optimized by the numerical simulations. Finally, two schemes were screened out for further laboratory tests. The retrofitting process shows that to retrofit the original combustor with natural gas as fuel for buming medium-heating-value syngas, the structure of the liner is hardly need to be changed, and the area of the fuel holes of the nozzle can be determined by keeping the same fuel jet velocity as that of the original combustor. However, the swirl number of the swirler should be increased.