Split Stream Flow Past a Blunt Trailing Edge with Application to Combustion Instabilities

Abstract

In shear coaxial injectors, commonly used for cryogenic liquid rocket engines, propellants traveling at different velocities are separated by the inner jet post before they come into contact with each other, mix, and combust. Knowing how the fluids mix and how susceptible they are to hydrodynamic instabilities is paramount for a successful liquid rocket engine. In this study, the wake behind a blunt trailing edge of a long plate, similar to an unwrapped coaxial injector, was studied in a water tunnel. Two fluid streams of different velocities were introduced on opposite sides of the plate. PIV was used to visualize and determine the influence of the velocity ratio of the split stream on the wake behavior. Measurements of the vortex shedding frequency were taken at various velocity ratios and compared with well characterized cases with a uniform free stream. Operating conditions ranged from Reynolds number 6,000 to 22,000 and velocity ratios 0.30 to 1.00.

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Document Details

Document Type
Technical Report
Publication Date
Aug 01, 2012
Accession Number
ADA572242

Entities

People

  • Beverley McKeon
  • Ivett Leyva
  • Vicky Tian

Organizations

  • Air Force Research Laboratory

Tags

Communities of Interest

  • Weapons Technologies

DTIC Thesaurus Topics

  • Air Force Research Laboratories
  • Boundary Layer
  • Engines
  • Flow
  • Fluid Dynamics
  • Fluid Flow
  • Fluid Mechanics
  • Free Stream
  • Frequency
  • Measurement
  • Reynolds Number
  • Rocket Engines
  • Strouhal Number
  • Trailing Edges
  • Turbulent Mixing
  • Vortex Shedding
  • Water Tunnels

Fields of Study

  • Physics

Readers

  • Aerodynamics.
  • Fluid Dynamics.
  • Rocket Propulsion.