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

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.

Subject Categories:

  • Jet and Gas Turbine Engines

Distribution Statement:

APPROVED FOR PUBLIC RELEASE