Focusing-schlieren visualization in a dual-mode scramjet

Toshinori Kouchi, Christopher P. Goyne, Robert D. Rockwell, James C. McDaniel

Research output: Contribution to journalArticle

11 Citations (Scopus)

Abstract

Schlieren imaging is particularly suited to measuring density gradients in compressible flowfields and can be used to capture shock waves and expansion fans, as well as the turbulent structures of mixing and wake flows. Conventional schlieren imaging, however, has difficulty clearly capturing such structures in long-duration supersonic combustion test facilities. This is because the severe flow temperatures locally change the refractive index of the window glass that is being used to provide optical access. On the other hand, focusing-schlieren imaging presents the potential of reduced sensitivity to thermal distortion of the windows and to clearly capture the flow structures even during a combustion test. This reduced sensitivity is due the technique’s ability to achieve a narrow depth of focus. As part of this study, a focusing-schlieren system was developed with a depth of focus near ±5 mm and was applied to a direct-connect, continuous-flow type, supersonic combustion test facility with a stagnation temperature near 1200 K. The present system was used to successfully visualize the flowfield inside a dual-mode scramjet. The imaging system captured combustion-induced volumetric expansion of the fuel jet and an anchored bifurcated shock wave at the trailing edge of the ramp fuel injector. This is the first time successful focusing-schlieren measurements have been reported for a dual-mode scramjet.

Original languageEnglish
Article number211
Pages (from-to)1-14
Number of pages14
JournalExperiments in Fluids
Volume56
Issue number12
DOIs
Publication statusPublished - Dec 1 2015

Fingerprint

supersonic combustion ramjet engines
Visualization
supersonic combustion
test facilities
shock waves
Test facilities
Imaging techniques
Shock waves
stagnation temperature
jet engine fuels
Schlieren systems
expansion
trailing edges
sensitivity
ramps
injectors
fans
wakes
Jet fuel
Flow structure

ASJC Scopus subject areas

  • Physics and Astronomy(all)
  • Fluid Flow and Transfer Processes
  • Computational Mechanics
  • Mechanics of Materials

Cite this

Focusing-schlieren visualization in a dual-mode scramjet. / Kouchi, Toshinori; Goyne, Christopher P.; Rockwell, Robert D.; McDaniel, James C.

In: Experiments in Fluids, Vol. 56, No. 12, 211, 01.12.2015, p. 1-14.

Research output: Contribution to journalArticle

Kouchi, T, Goyne, CP, Rockwell, RD & McDaniel, JC 2015, 'Focusing-schlieren visualization in a dual-mode scramjet', Experiments in Fluids, vol. 56, no. 12, 211, pp. 1-14. https://doi.org/10.1007/s00348-015-2081-9
Kouchi, Toshinori ; Goyne, Christopher P. ; Rockwell, Robert D. ; McDaniel, James C. / Focusing-schlieren visualization in a dual-mode scramjet. In: Experiments in Fluids. 2015 ; Vol. 56, No. 12. pp. 1-14.
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