Analysis of low-swirl injector emissions and combustion stabilization

Low-swirl combustion technology based on low-swirl injector (LSI) has an ability of ultra-low emission. The principle of the low-swirl combustion stabilization and emissions reduction was analyzed; it was found that its special flowfield structure matching the turbulent flame propagation was a key factor for combustion stabilization and pollution emissions. Key parameters such as the vane angle, radius ratio and mass flow ratio, could impact the downstream flow characteristics of LSI, which would further affect the combustion performance. Fuels impact the combustion stabilization and pollution emissions of LSI by the flame speed and adiabatic flame temperature. To apply the liquid fuel in LSI, the premixed prevaporised combustion was adopted at present, and the experimental results indicated that it could reduce 10%-60% of NOx emissions compared with the traditional high swirl injector combustor, along with a risk of autoignition and flashback. And for LSI spray combustion, more basic researches on the liquid spray combustion in low-swirl flow shall be required. It is difficult to develop next-generation ultra-low emission combustor for aero-engines different from the traditional high-swirl combustion, unless solving the application problem of LSI using liquid fuel.