Fundamental Investigations of an Integrated Fuel Injector/Flameholder Concept for Supersonic Combustion
Abstract
This report describes the results of a recent series of experiments designed to examine the fundamental behavior of several cavity-based flameholder candidates in a non-reacting supersonic flow. Seven geometries were tested in conjunction with a new facility nozzle. Results indicate that the cavity aft ramp plays a strong role in determining the character of the shear layer which spans the length of the cavity. For rectangular cavities, a compression wave forms as the flow separates from the upstream corner of the cavity. Thus, the pressure on the upstream face increases above the freestream value. In these cases, the recompression which occurs at the aft wall is very sharp with strong pressure gradients at the axial location corresponding to the aft wall. These cases are also visibly unsteady. Reductions in the ramp angle yield more stable, two-dimensional flowfields. However, the character of the separation wave changes gradually from compressive to expansive as the ramp angle is reduced. As such, the shear layer tends to dip into the cavity and the recompression occurs more gradually as the shear layer reattaches to the aft wall. Changes in cavity offset ratio result in more dramatic changes in the cavity flowfield. The separation wave becomes strongly expansive leading to severe shear layer intrusion into the cavity. Aft wall changes do not strongly impact the character of the shear layer, although stability is enhanced and recompression is more gradual for shallower ramp angles.
Document Details
- Document Type
- Technical Report
- Publication Date
- Sep 01, 1998
- Accession Number
- ADA356336
Entities
People
- Mark R. Gruber
Organizations
- Air Force Research Laboratory