The Effects of Pressure and Acoustic Field on a Cryogenic Coaxial Jet
Abstract
A coaxial injector was designed to inject liquid nitrogen (LN2) with a coflow of gaseous nitrogen (GN2) in its annular region as part of a program to better understand the nature of the interaction between acoustic waves and liquid the jets in cryogenic rocket engines. Backlit images were taken from the jets at various flow rates and at sub-, near-, and super-critical chamber pressures with and without the presence of a 2700 Hz standing wave acoustic field. injector exit plane temperature measurements were made in both the center jet and annular regions. Results indicate that when the jet core appeared short and "thin", mostly under supercritical chamber pressures, the jet became insensitive to the external acoustic field. The strongest interaction was observed when the jet core looked long and "thick". To explore their implications, the characteristic acoustic impedance of the central jet and fuel/oxidizer momentum ratios are considered to play a role in the observed interactions. It is feasible that they play a similar role in cryogenic rocket engine combustion instability of the coaxial jet.
Document Details
- Document Type
- Technical Report
- Publication Date
- Dec 16, 2003
- Accession Number
- ADA419454
Entities
People
- B. Chehroudi
- Dustin Davis