富氢燃料贫预混旋流燃烧中热声振荡驱动机理研究

Lean-premixed combustion appears to be the most promising technology for the low emission combustion of hydrogen-enriched fuel in gas turbine, but it is easy to appear thermoacoustic oscillation. These oscillations may reach sufficient amplitudes to interfere with combustion process, enhance pollutant emissions, and in extreme cases, lead to failure of the system structurally. However, the driving mechanisms of thermoacoustic oscillation in lean-premixed swirl-stabilized combustion process have not been identified clearly. In addition, comparing to traditional fuel, hydrogen-enriched fuel has faster flame speed and shorter autoigniton delay time, and those make the problem of thermoacoustic oscillation more serious. Thus, the effects of "vortex-flame interaction" in driving thermoacoustic oscillation in hydrogen-enriched fuel's lean-premixed swirl-stabilized combustion are researched with experimental measurement, unsteady numerical simulation and nonlinear theoretical analysis. The main contents include the interaction of PVC and flame, combustion characters of fuel, swirler structures, and operational parameters' effects on the driving mechanisms of thermoacoustic oscillation. Finally，effective methods are given to suppress thermoacoustic oscillation, and theoretical supports are given to ensure the safety, efficient, clear and stable lean-premixed swirl-stabilized combustion of hydrogen-rich fuels.

贫预混燃烧是实现富氢燃料燃气轮机低污染燃烧的最有前景的技术途径之一，然而贫预混燃烧中容易出现热声振荡问题。热声振荡诱发的低频高幅的压力振荡会干扰燃烧过程，增大污染物的排放，严重时会对整个燃烧系统造成结构性的破坏。然而目前贫预混旋流燃烧中的热声振荡的驱动机理仍未完全明确，而且相对于传统燃料，富氢燃料的火焰传播速度更快、自点火延迟时间更短，使富氢燃料贫预混旋流燃烧中的热声振荡问题更加突出。本项目拟通过实验研究、非定常数值模拟和非线性理论分析相结合的手段，研究富氢燃料贫预混旋流燃烧中旋涡-火焰相互作用驱动热声振荡的机理，主要包括：PVC-火焰相互作用、燃料燃烧特性、旋流器结构、以及状态参数对热声振荡的影响机制的研究。然后提出抑制热声振荡的有效途径，为设计安全、高效、清洁、稳定的富氢燃料贫旋流预混燃烧室提供理论上的支持。

贫预混燃烧是实现富氢燃料燃气轮机低污染燃烧的最有前景的技术途径之一，然而贫预混燃烧中容易出现热声振荡问题。热声振荡诱发的低频高幅的压力振荡会干扰燃烧过程，增大污染物的排放，严重时会对整个燃烧系统造成结构性的破坏。然而目前贫预混旋流燃烧中的热声振荡的驱动机理仍未完全明确，而且相对于传统燃料，富氢燃料的火焰传播速度更快、自点火延迟时间更短，使富氢燃料贫预混旋流燃烧中的热声振荡问题更加突出。本项目首先通过数值模拟的手段获得了结构参数对富氢燃料流场和火焰形态的影响,然后利用CHEMKIN计算了组分对火焰速度的影响,并试验获得了燃料组分、状态参数对热声振荡的影响规律，最后利用理论分析方法构建了动态热释放模型、数值计算和试验研究了火焰面波动与热声振荡的机理。通过上述研究，为设计安全、高效、清洁、稳定的富氢燃料贫旋流预混燃烧室提供理论上的支持。