Pulsed Injection for Nozzle Throat Area Control
Abstract
Computational fluid dynamics (CFD) and experimental methods were used to investigate two unsteady injection techniques for increasing the penetration and blockage of an injected stream in a confined, expanding crossflow. The obstruction produced by an injected stream is a basic mechanism related to the efficacy of fluidic nozzle control techniques. A CFD simulation methodology was developed for unsteady injection, which showed the effects of grid resolution, turbulence model, and numerical discretization on solution accuracy. CFD simulations were used to explore the basic effects of injector pulsing frequency, Mach number, and geometry on injector-jet trajectory, penetration, diameter, and blockage in a nozzle crossflow. Two actuators were experimentally evaluated for pulsing an injected stream that issues into a nozzle crossflow. CFD simulations were also used to investigate a pulsed-ejection technique, which used a pulsed high- pressure primary stream to boost the entrainment of a co-annular, low-pressure secondary flow. Simulations revealed the effects of primary-jet pulsing frequency and ejector geometry on ejector pumping effectiveness relative to a steady-jet ejector. A simplified CFD model was developed to capture the essential effect of the unsteady primary stream on the secondary flow, without the need of a highly resolved simulation. Results of CFD solutions were compared with available data.
Document Details
- Document Type
- Technical Report
- Publication Date
- Feb 05, 2001
- Accession Number
- ADA387488
Entities
People
- Brian R. Smith
- Daniel N. Miller
- Erich E. Bender
- K. B. Ginn
- Patrick J. Yagle
Organizations
- Lockheed Martin