旋流预混燃烧室燃烧特性及排放特性的数值模拟研究

为了综合考察燃气轮机燃烧室在高稳定性、低排放以及燃料适应性等方面的新要求，基于旋流预混燃烧技术，通过三维数值模拟方法开展了甲烷/空气、丙烷/空气预混燃烧特性及排放特性研究。结果表明：在一定的预混气进气质量流量条件下，当量比增大易引发回火，燃烧温度更高，同时NO_x排放指数增大，增加预混气质量流量，可在一定程度上提高回/熄火极限；当量比固定，增加预混气进气质量流量可避免潜在的回火现象，且NO_x排放指数线性降低；旋流器的旋流数增大能形成强旋流，稳定火焰，降低NO_x排放指数，但过大的旋流强度会引发回火现象；相比于甲烷/空气预混燃烧，丙烷/空气预混燃烧温度偏高，NO_x排放指数较大，但回熄火边界更宽，对应更广阔的稳定燃烧区间。

Numerical simulation study on combustion and emission characteristics in a swirl premixed combustor

In order to comprehensively investigate the new requirements of gas turbine combustors in terms of high stability, low emissions and fuel adaptability, the methane/air and propane/air premixed combustion and emissions characteristics were studied through three dimensional numerical simulation based on swirl premixed combustion technology. The results show that the increase of equivalence ratio will lead to flashback under certain air intake mass flow rate of premixed air, the NOx emission index increases due to higher combustion temperature, and the flashback/flameout limit tends to extend under higher premixed air mass flow rate; under constant equivalence ratio, potential flashback phenomenon will be avoided by increasing air intake mass flow rate of premixed air, and the emission index decreases linearly; the increment of swirl number can generate strong swirl to stabilize flame and reduce NOx emission index, but excessive swirl intensity will lead to flashback; compared with methane/air premixed combustion, propane/air premixed combustion temperature is higher and NOx emission index is bigger, but the boundary between flashback and flameout is wider, corresponding to wider stable combustion region.