Supersonic Base Flow Problem in Presence of an Exhaust Jet

Wagner, Bernhard; White, Robert A.

doi:10.2514/3.50829

Cited by 10 publications

(1 citation statement)

References 7 publications

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“…The high intensity region of the OH radicals moved from the vicinity of the recirculation zone to the center of the flame, because the centerline stagnation point may have acted as an effective source of fuel. The anchoring point of this supersonic flame was at the outer edge of the outside recirculation zone near the exit of the bluff-body fuel tube, as suggested by others [25,26], and the actual reaction occurred at the end position of shock structure, as shown in the Schlieren image and photograph in Fig. 7d.…”

Section: Effect Of Coflow On Supersonic Flamesmentioning

confidence: 87%

The Characteristic Modes and Structures of Bluff-Body Stabilized Flames in Supersonic Coflow Air

Kim

Yoon

Park

et al. 2012

International Journal of Aeronautical and Space Sciences

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The stability and structure of bluff-body stabilized hydrogen flames were investigated numerically and experimentally. The velocity of coflowing air was varied from subsonic velocity to a supersonic velocity of Mach 1.8. OH PLIF images and Schlieren images were used for analysis. Flame regimes were used to classify the characteristic flame modes according to the variation of the fuel-air velocity ratio, into jet-like flame, central-jet-dominated flame, and recirculation zone flame. Stability curves were drawn to find the blowout regimes and to show the improvement in flame stability with increasing lip thickness of the fuel tube, which acts as a bluff-body. These curves collapse to a single line when the blowout curves are normalized by the size of the bluff-body. The variation of flame length with the increase in air flow rate was also investigated. In the subsonic coflow condition, the flame length decreased significantly, but in the supersonic coflow condition, the flame length increased slowly and finally reached a near-constant value. This phenomenon is attributed to the air-entrainment of subsonic flow and the compressibility effect of supersonic flow. The closed-tip recirculation zone flames in supersonic coflow had a reacting core in the partially premixed zone, where the fuel jet lost its momentum due to the high-pressure zone and followed the recirculation zone; this behavior resulted in the long characteristic time for the fuel-air mixing.

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Section: Effect Of Coflow On Supersonic Flamesmentioning

confidence: 87%