Combustion Enhancements in Advanced Liquid Rocket Engines.
Abstract
A series of liquid jet experiments, utilizing water as the working fluid and an optically accessible orifice with a LID ratio of 2.5, were performed using laser velocimetry to map the velocity profile at several locations within the orifice. Additional measurements were also made downstream of the orifice exit in the free jet. Finally, measurements were made for a 300 angled orifice to more closely simulate actual injector conditions. The key objective in pursuing these measurements was to determine if a correlation existed between the turbulent structures within the jet and the formation of impact waves after impingement. A link between these waves, which may play a role in combustion instability, and the boundary layer characteristics could then be used to suggest remedies for combustion instability through boundary layer modification. Velocity profile comparisons revealed no alternation of the boundary layer or turbulence characteristics. Preliminary measurements were also made in the free jet, just prior to the point of impingement. Comparison of these results revealed a significant difference between the velocity profiles and the axial turbulence intensity profiles. In particular, the impingement widens the jet and increases the turbulence found in the flow field. However, the earlier measurements indicate these disturbances did not propagate upstream to the orifice. Thus, based on this work, boundary layer thickness and turbulence effects produced in the orifice were eliminated as a mechanism for generating combustion instability in rocket combustors using impinging jet injectors. Consequentially, boundary layer modification does not appear to represent an effective approach to suppress combustion instability for these injectors.
Document Details
- Document Type
- Technical Report
- Publication Date
- May 17, 1999
- Accession Number
- ADA365975
Entities
People
- Robert J. Santoro
Organizations
- Pennsylvania State University