轴向双级反旋预混喷嘴燃烧调整边界实验研究

Experimental Research on Mapping Boundary of Axial Double Annular Counter-Rotating Swirler

关键词:  燃气轮机  干式低污染燃烧室  双级反向旋流器  调整边界  热声振荡

Key words:  Gas turbine  Dry low emission combustor  Double annular counter-rotating swirler  Mapping boundary  Thermoacoustic oscillation

摘要:

干式低污染燃烧室为保证安全、稳定、高效的运行状态，通常需要进行燃烧调整。本文针对一种干式低污染燃烧室用轴向双级反旋预混喷嘴，在常温常压条件下开展燃烧调整边界实验研究。测量并探究了影响燃烧调整边界的因素，如贫熄火边界、污染物排放边界以及动态压力脉动边界，着重分析了喷嘴内的剪切层稳焰机理以及火焰根部跳动与壁面相干作用导致的热声振荡机理。研究结果表明，由NO_x、CO、火焰状态、动态压力脉动和熄火边界共同决定的稳定运行边界在低负荷条件下为当量比0.576~0.714，随着热负荷升高，运行边界有所收窄。对比分析了纯甲烷以及掺50%H₂两种燃料的燃烧调整边界，燃料加氢后边界整体向低当量比移动，运行窗口宽度得到拓展。

Abstract:

Combustion mapping is used to ensure a safe， stable and efficient operation condition of dry low emission combustion chamber. The mapping boundary of combustion chamber was tested in a double annular counter rotating swirler used in dry low emission combustion chamber at normal temperature and pressure condition. Factors affecting the mapping boundary were investigated， including lean blow-out characteristics， emission boundary and dynamic pressure pulsation boundary. Flame stabilization mechanism of the shear layer in the swirler and the thermoacoustic oscillation mechanism caused by flame root pulsation and wall coherence were analyzed emphatically. The result shows that the stable mapping boundary， which is jointly determined by NO_x， CO， flame state， dynamic pressure pulsation and flameout boundary， is roughly in the range of 0.576~0.714 equivalent ratio in low power condition. With the increase of power load， mapping boundary becomes narrower.Then the mapping boundary of pure methane and hydrogen blend natural gas is compared and analyzed. After 50% hydrogen was blended in the fuel， the bulk boundary moves to a lower equivalent ratio， and operation window gets expanded.