Investigation of Coaxial LN2/GH2-Injection at Supercritical Pressure by Spontaneous Raman Scattering

Abstract

In high pressure LOX/GH2-rocket combustors cryogenic oxygen is injected at pressures above its critical pressure of 5.04 MPa. At the cryo-injector test facility at DLR Lampoldshausen the injection of cryogenic nitrogen can be investigated at pressures up to 6MPa, 1.76 times the critical pressure of nitrogen. Thus the influence of real gas behaviour on the atomisation process can be analysed experimentally under idealised conditions, without the interaction with combustion as in real rocket engines. The break-up of a cryogenic nitrogen jet has been investigated using spontaneous Raman scattering without and with coaxial injection of hydrogen. For several injection conditions radial density profiles of nitrogen and hydrogen has been obtained as a function of the location downstream the injector.