Accession Number:
ADA224145
Title:
Numerical Simulations of Flowfields in a Central-Dump Ramjet Combustor. 3. Effects of Chemistry
Descriptive Note:
Interim rept.
Corporate Author:
NAVAL RESEARCH LAB WASHINGTON DC
Personal Author(s):
Report Date:
1990-07-23
Pagination or Media Count:
52.0
Abstract:
This report is the third in a series which presents the results of numerical simulations performed to isolate and study acoustic-vortex-chemical interactions in an idealized ramjet consisting of an axisymmetric inlet and combustor and a choked nozzle. Both reactive and nonreactive flows have been simulated. The nonreactive flow calculations show complex interactions among the natural instability frequency of the shear layer at the inlet-combustor junction and the acoustics of both the inlet and the combustor. The entire flow oscillates at a low frequency which corresponds to that of a quarter-mode in the inlet. For the reactive flow cases studied, energy release alters the flow field substantially. Energy release in a large vortex is in phase with the pressure oscillation over a substantial region of the combustor and results in the observed amplification of the low-frequency oscillations and leads to combustion instability. The large pressure oscillation also modifies the vortex shedding process. Keywords Ramjet, Turbulence, Combustion instability.
Descriptors:
- *COMBUSTORS
- VARIABLE PRESSURE
- COMPUTATIONS
- REACTION KINETICS
- INTERACTIONS
- LAYERS
- NUMERICAL ANALYSIS
- TURBULENCE
- ENERGY TRANSFER
- VORTICES
- VORTEX SHEDDING
- REGIONS
- CHEMISTRY
- RESONANT FREQUENCY
- FLOW FIELDS
- AXISYMMETRIC
- ACOUSTICS
- FLOW
- COMBUSTION STABILITY
- JUNCTIONS
- OSCILLATION
- INLETS
- LOW FREQUENCY
- SHEAR PROPERTIES
- STABILITY
Subject Categories:
- Jet and Gas Turbine Engines