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Cavity-actuated supersonic mixing and combustion control
- Source :
- Combustion and Flame. 99:295-301
- Publication Year :
- 1994
- Publisher :
- Elsevier BV, 1994.
-
Abstract
- 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 c ) of 0.85 by a factor of three. For high-temperature Mach 2.0 jets with M 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.
- Subjects :
- Convection
Chemistry
General Chemical Engineering
General Physics and Astronomy
Energy Engineering and Power Technology
Thermodynamics
Fluid mechanics
General Chemistry
Mechanics
Physics::Fluid Dynamics
symbols.namesake
Fuel Technology
Mach number
Compressibility
symbols
Fluid dynamics
Supersonic speed
Shear flow
Choked flow
Subjects
Details
- ISSN :
- 00102180
- Volume :
- 99
- Database :
- OpenAIRE
- Journal :
- Combustion and Flame
- Accession number :
- edsair.doi...........a139391d7af533820967981e509bb457