天然气掺氢燃烧是燃气轮机机组降低碳排放重要措施之一,但掺氢燃料的组分变化会导致燃烧室火焰结构及燃烧稳定性发生变化.为分析中心分级燃烧器掺氢燃烧条件下的燃烧不稳定性问题,通过试验研究了燃烧器入口速度扰动下,不同掺氢比对中心分级掺氢燃烧的瞬态火焰结构、压力以及热释放响应的影响,并利用本征正交分解(POD)法提取了火焰脉动的特征模态,发现其主要包含火焰干涉区强脉动和轴向扰动两种模态.试验结果表明,随着掺氢体积比从0%增大到30%,火焰前沿向上游移动,两级火焰间距缩短,火焰干涉对应的脉动模态的能量占比增大,加强了压力与热释放的耦合,导致燃烧室内的压力响应增大9%,热释放响应增大37%.

Natural gas mixed with hydrogen combustion is one of the important measures to reduce carbon emissions of gas turbine. However, the composition change of fuel will lead to changes in the flame structure and combustion stability of the combustor. In order to analyze the combustion instability of natural gas mixed with hydrogen combustion in the central staged burner, the effects of different hydrogen doping ratios on the transient flame structure, pressure and heat release response of the central staged combustion are experimentally studied. The proper orthogonal decomposition (POD) method is used to extract the characteristic modes of flame pulsation. It is found that the flame pulsation mainly includes two modes: a strong pulsation in the interference zone of flame and an axial disturbance. The experimental results show that as the volume ratio of hydrogen doped increases from 0% to 30%, the flame front moves upstream, the spacing between two staged flames is shortened, the energy proportion of pulsation mode corresponding to the flame interference increases, and the coupling of pressure and heat release is strengthened, which ultimately results in a 9% increase in pressure response and a 37% increase in heat release response in the combustor.