Accession Number:

ADA172904

Title:

Basic Instability Mechanisms in Chemically Reacting Subsonic and Supersonic Flows.

Descriptive Note:

Annual rept. 30 Sep 84-29 Sep 85,

Corporate Author:

MASSACHUSETTS INST OF TECH CAMBRIDGE

Personal Author(s):

• Toong,Tau-Yi

Report Date:

1985-10-21

Pagination or Media Count:

28.0

Abstract:

Both theoretical and experimental studies were conducted to determine and elucidate major mechanisms governing turbulence-combustion interactions. The theoretical study showed the importance of wrinkling-like effects as well as the effects of the chemical reaction rate on the evolution of fluctuations in streamwise- and transverse-velocity, temperature, concentration, and vorticity in a shear layer. The wrinkling-like effects were induced by the transverse-velocity fluctuations in nonuniform mean flows. The direct rate-augmentation effects due to reaction led to changes in phase relationships between the various fluctuations, resulting in turbulent energy and mass transport in a direction opposite to that suggested by the gradient model in that part of the shear layer nearer the unreacted region. The experimental study showed the effects of adding ethane at the same overall equivalence ratio on the thermal structure of methaneair flames. Temperature fluctuations were augmented by ethane addition, the highest augmentation being observed at 10-ethane addition. A one-component Laser-Doppler-Velocimetry system was installed and tested.

Descriptors:

• *TURBULENCE
• *COMBUSTION
• SHEAR PROPERTIES
• TEMPERATURE
• REACTION KINETICS
• INTERACTIONS
• VORTICES
• CHEMICAL REACTIONS
• MASS TRANSFER
• SUBSONIC FLOW
• FLAMES
• VELOCIMETERS
• FLAME PROPAGATION
• COMBUSTION STABILITY
• SUPERSONIC FLOW
• ETHANES
• CONCENTRATION(CHEMISTRY)

Subject Categories:

• Fluid Mechanics
• Air Breathing Engines (Unconventional)
• Combustion and Ignition

Distribution Statement:

APPROVED FOR PUBLIC RELEASE