Qualitative investigation of cryogenic fluid injection into a supersonic flow field

The behavior of liquid nitrogen injected into a supersonic nitrogen flow field was investigated using an experimental apparatus in which a Mach 2.7 2D gas nitrogen tunnel is coupled with a high-pressure cryogenic source. Observations were monitored and recorded via a video camera and a motion picture camera. It was found that the penetration of a supersonic flow field by injection of liquid nitrogen is strongly dependent on the flow Mach number, the cryogen injection pressure (Pi/Pc), the injector configuration, and the cryogen temperature. For a 2D gaseous N2, Mach 2.7 tunnel, with cryogen injection Pi/Pc approaching 2, the injected fluid penetration for the 1/8-in. injection port approached one half of the tunnel width at 90-deg injection, and one fourth of the tunnel width at 20-deg injection.