基于斜坡限制域对掺氢旋流火焰燃烧振荡的被动控制

Hydrogen has immense potential for reducing carbon emissions， but compared to methane， it exhibits more severe combustion oscillations. This study investigates the macrostructure and spectral characteristics of hydrogen-enriched methane flames under different hydrogen volume ratios. To thoroughly investigate the dynamic evolution process of hydrogen-enriched swirling flames， this study employed both single-lens reflex cameras and high-speed cameras to capture the time-averaged and instantaneous flame images， respectively. The dynamic characteristics of the flames were then analyzed using various methods， including proper orthogonal decomposition ， Rayleigh index distribution， and root mean square distribution. Experimental tests were conducted using a stratified swirl burner， varying hydrogen volume ratio and primary air flow rate of the main stage under atmospheric conditions. The results show that axial flame instability is the main source of combustion instability in hydrogen-enriched methane flames. The slope confinement exhibits significant damping effects on combustion instability compared to conventional dump confinement and the maximum reduction in pressure fluctuation reached 95%.