Investigation of a combustion driven oscillation in a refinery flare. Part A: Full scale assessment

摘要: Abstract An assessment of the cause an intermittent combustion-driven oscillation in a full-scale refinery flare is reported. When present, ambient sound pressure levels excess 100 dBA are generated. The oscillations began after replacement old tip with one different design which required use non-standard components. included measurements time resolved and integrated environment, fuel pipe air duct. Images obtained from video recorded two directions presented along relevant process data. A review also conditions under inhibited or enhanced, comparison made another similar does not exhibit oscillation. Strouhal numbers potential causes flow wavelength acoustic resonances supply pipes calculated. findings then compared related investigations found literature. frequency was to scale speed match resonant within three consecutive segments pipe. In contrast, constant for all tests, while varied. This shows that resonance occurs system. scales approximately flow-rate, although more poorly than sound, matches vortex shedding deduced be present side tip. addition fundamental jet emerging At same visual appearance base flame consistent being driven at its mode. suggests caused by coincidence several coupling mechanisms. control amplify fluctuations. However root supply. fluctuations rate amplified heat release. creates positive feedback further amplifying resonance.