Focusing-schlieren visualization in direct-connect dual-mode scramjet

Toshinori Kouchi, Christopher P. Goyne, Robert D. Rockwell, Roger Reynolds, Roland Krauss, James C. McDaniel

Research output: Chapter in Book/Report/Conference proceedingConference contribution

7 Citations (Scopus)

Abstract

Schlieren imaging has high sensitivity for density gradient in a flow field, and easily captures not only shock and expansion waves but also turbulent structures in the flow field. The conventional schlieren imaging, however, cannot capture clearly them in directconnect supersonic combustor tests with long duration, because the severe temperature condition in the combustor locally changes the refractive index of the window glasses for optical access. The conventional schlieren technique is essentially sensitive to the entire region of the light path including the glasses. On the other hand, focusing-schlieren technique has narrow depth of focus. Therefore, the imaging is expected to avoid the thermal distortion of the glasses. In this work, we applied focusing-schlieren imaging to the supersonic combustion tests, and tried to clearly capture the flow features inside a dualmode scramjet. The present system had about ± 5 mm depth of focus, and successfully visualized the flow field in the combustor, though the system sensitivity declined with the tunnel heating up. Combustion drastically changed the flow field inside the combustor, and induced volumetric expansion of fuel jet, resulting in pressure rise. Combustiongenerated pressure rise pushed up the shock train up to the trilling edge of the ramp fuel injector. The system recorded two image pairs by using PIV system. These image pairs yielded the convection velocity of turbulent structures in the combustor.

Original languageEnglish
Title of host publication18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012
Publication statusPublished - Dec 1 2012
Event18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012 - Tours, France
Duration: Sep 24 2012Sep 28 2012

Publication series

Name18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012

Other

Other18th AIAA/3AF International Space Planes and Hypersonic Systems and Technologies Conference 2012
CountryFrance
CityTours
Period9/24/129/28/12

ASJC Scopus subject areas

  • Space and Planetary Science
  • Aerospace Engineering
  • Control and Systems Engineering

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