Measurements of a Simulated Rocket Exhaust Plume near the Prandtl-Meyer Limiting Angle,

Abstract : Direct measurements of the mass flux level and estimates of the mass velocity have been made in the side flow field of a small axisymmetric rocket nozzle operated in hard vacuum. A shock tube provided nitrogen and simulated rocket propellant (nitrogen tetroxide and Aerozene 50) sources for the nozzle. Data were recorded in the plume far field, for angles ranging from 0 to 90 degrees relative to the nozzle centerline. In all cases, substantial mass flux levels were observed in the neighborhood of the limiting Prandtl-Meyer characteristic. At an angle of 90 degrees to the nozzle centerline, the density levels were typically three orders of magnitude below centerline values and the mass velocities were approximately one-half of the centerline values. (Modified author abstract)