Preliminary Results on the Effect of Phase Angle on Coaxial Jet Behavior spanning Sub- to Supercritical Pressures
Conference Paper
Overview
Overview
abstract
This paper describes the effects of phase angle of an acoustic pressure field on a shear coaxial jet. The jet is forced with a transverse acoustic field, made up of two acoustics sources with pRMS/pmean up to 3.1%. The chamber pressure ranges from 1.5 to 5.0 MPa. The momentum flux ratio (MR) between the outer and inner jet varies from 0.02 to 23 and the velocity ratio from 0.25 to 23. The shear coaxial geometry is selected because of its application to liquid rocket engines. The jet was analyzed by taking high speed images and exit-plane temperature measurements. This work continues previous work where the jet was excited with one acoustic source; therefore the jet location was fixed with respect to the acoustic field. For nearcritical pressures, the cases with MR<1 and MR>9 were least sensitive to the acoustic field and phase angles. For the cases, MR=1.1 to 4.9 the trends of L/D qualitatively followed the p field trends. The maximum L/D was found around the maximum value of p and viceversa. For these data, it seems like the dark core length is more affected, in terms of its reduction, by high acoustic velocity amplitude and not high pressure amplitudes.
