Accession Number:

AD1078102

Title:

Preliminary Study of the Reacting Flow from Multi-Element Shear Coaxial Flows (Conference Paper with Briefing Charts)

Descriptive Note:

Conference Paper,01 May 2018,06 Feb 2019

Corporate Author:

AIR FORCE RESEARCH LAB EDWARDS AFB CA EDWARDS AFB United States

Personal Author(s):

Report Date:

2018-05-21

Pagination or Media Count:

35.0

Abstract:

The reacting flow dynamics from a linear array of three shear coaxial injectors operating under sub-critical pressures was investigated. High-speed images recorded the center injectors response and behavior under the influence of its neighboring injectors for both acoustically unforced and forced conditions. The injectors employed liquid rocket engine relevant propellants of gaseous hydrogen and liquid oxygen. High-speed shadowgraph images along with OH chemiluminescence captured the hydrodynamic instabilities for each injector and the flame interactions. Overlapping OH chemiluminescence on top of the shadowgraph images, similar vortexflame interactions were observed as were observed for a single jet for each individual jet from the injector. Spectral analysis on the OH chemiluminescence in the near field shows that the individual flames share similar frequency fluctuations when the multi-element array was not subjected to acoustic forcing. These frequencies were also present in the dynamic mode decomposition of the shadowgraph and OH chemiluminescence images used to investigate the modal structures of both the LOX jet and flame, respectively. Under acoustic forcing, the modal structures of both the LOX jet and flame are the same from each injector.

Subject Categories:

  • Fluid Mechanics
  • Combustion and Ignition

Distribution Statement:

APPROVED FOR PUBLIC RELEASE