Forced flaming

In multiple combustion installations all combustors are interconnected by tubes located near the upstream ring of perforations. Ignitors are provided in only some of the combustors. When one combustor lights, the sudden increase in pressure loss forces flame through the interconnecting tubes to the adjacent combustors, immediately lighting the other combustors. 

The controlled flame was found to be largely unaffected by moderate swirl (levels up to 40%) although the stability was slightly reduced. Heavy swirl (beyond 75%) led to a further reduction in stability and intermittent formation of soot. The unforced swirling flame was not nearly as efficient in reducing soot formation as the controlled (forced) flame without swirl. The flame was unstable, quite yellow, and spread out to impinge upon the dump diameter... 

Air forcing had a significant effect on the flame structure. At the baseline conditions, the flame was lifted and sooty. With air forcing, the flame became fully reattached to the flame holder. Swirl had little effect on the structure of a highly forced flame. 

Liquid-fuel pulsations proved to be most effective in a forced flame. Injecting fuel in-phase with air vortices provided the highest temperatures. In both nonswirling and swirling flames, injecting fuel out of phase with air vortices proved to be least efficient. 

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