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Creators/Authors contains: "Birkbeck, Christopher"

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  1. ; ; ; ; (, Combustion Institute)
    Abstract: Lean premixed (LP) combustion systems are currently used for most modern power generation gas turbines. Though this method reduces emissions, specifically nitrogen oxides, and is more efficient than non-premixed systems, LP systems are susceptible to blowoff. The goal of this study is to find out how centerbody geometry plays a role in the lean blowoff process for swirl-stabilized flames. We find that cylindrical centerbodies have higher lean blowoff equivalence ratios than tapered centerbodies. We also find that the dominant flame shape for both centerbodies is M-shape when not anchored and tulip shaped when anchored, though the tapered centerbodies induce V-shape flames as well. The blowoff equivalence ratio and blowoff process are strongly coupled ith the flame shape. 
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    Accepted Manuscript Full Text Available
  2. ; ; ; ; ; ; (, Combustion Institute)
    This work focused on understanding how swirl influences the blowoff limit and process in lean-premixed, swirl-stabilized flames. Two initial equivalence ratios (Ф0 = 0.8 and 1.0) were used to study the effect of swirl number (S = 0.80, 0.95, 1.15, and 1.43) on the lean blowoff limits. It was seen that at higher Ф0, the blowoff equivalence ratio of flames with lower swirl levels was typically more sensitive to bulk flow velocities than flames stabilized at lower Ф0. The blowoff Ф of flames stabilized at higher swirl levels did not vary much with an increase in bulk flow velocity. Global CH* chemiluminescence was done to study the lean blowoff process further. At lower Ф0 and swirl levels, the occurrence of the extinction/reignition events in the shear layers seemed more prominent. 
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    Accepted Manuscript Full Text Available