Cavity-actuated supersonic mixing and combustion control

Conference · Tue Nov 01 04:00:00 EST 1994 · Combustion and Flame; (United States)

OSTI ID:6537727

Yu, K H; Schadow, K C ^[1]

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1. Naval Air Warfare Center, China Lake, CA (United States). Research Dept.

Compressible shear layers in supersonic jets are quite stable and spread very slowly compared with incompressible shear layers. In this paper, a novel use of a cavity-actuated forcing technique is demonstrated for increasing the spreading rate of compressible shear layers. Periodic modulations were applied to Mach 2.0 reacting and nonreacting jets using the cavities that were attached at the exit of a circular supersonic nozzle. The effect of cavity-actuated forcing was studied as a function of the cavity geometry, in particular, the length and the depth of the cavity. When the cavities were tuned to certain frequencies, large-scale highly coherent structures were produced in the shear layers substantially increasing the growth rate. The cavity excitation was successfully applied to both cold and hot supersonic jets. When applied to cold Mach 2.0 air jets. the cavity-actuated forcing increased the spreading rate of the initial shear layers with the convective Mach number (M[sub C]) of 0.85 by a factor of three. For high-temperature Mach 2.0 jets with M[sub C] of 1.4, a 50% increase in the spreading rate was observed with the forcing. Finally, the cavity-actuated forcing was applied to reacting supersonic jets with ethylene-oxygen afterburning. For this case, the forcing caused a 20%--30% reduction in the afterburning flame length and modified the afterburning intensity significantly. The direction of the modification depended on the characteristics of the afterburning flames. The intensity was reduced with forcing for unstable flames with weak afterburning while it was increased for stable flames with strong afterburning.

• OSTI ID: 6537727
• Report Number(s): CONF-940711--
• Conference Information: Journal Name: Combustion and Flame; (United States) Journal Volume: 99:2
• Country of Publication: United States
• Language: English

Related Subjects

02 PETROLEUM
025000 -- Petroleum-- Combustion
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
400800* -- Combustion
Pyrolysis
& High-Temperature Chemistry
AFTERBURNERS
ALKENES
COMBUSTION CONTROL
COMPRESSIBILITY
CONTROL
EQUIPMENT
ETHYLENE
FLAMES
FLUID FLOW
FLUID MECHANICS
HYDROCARBONS
MECHANICAL PROPERTIES
MECHANICS
ORGANIC COMPOUNDS
POLLUTION CONTROL EQUIPMENT
STABILITY
SUPERSONIC FLOW