Analytical and Experimental Evaluation of Aerodynamic Thrust Vectoring on an Aerospike Nozzle

Results from numerical and coldow experimental investigations of aerodynamic thrust vectoring on a small-scale aerospike thruster are presented. Thrust vectoring was created by the injection of a secondary uid into the primary ow eld normal to the nozzle axis. The experimental aerospike nozzle was truncated at 57% of its full theoretical length. Data derived from coldow thrust vectoring tests with carbon dioxide as the working uid are presented. Injection points near the end of the truncated spike produced the highest force ampli cation factors. Explanations are given for this phenomenon. For secondary injection near the end of the aerospike, side force ampli cation factors up to approximately 1.4 and side force speci c impulses up to approximately 55 s with main ow speci c impulses clustering around 38 s were demonstrated. These forces crisply reproduce input pulses with a high degree of delity. The side force levels are approximately 2.7% of the total thrust level at maximum e ectiveness. Higher side forces on the order of 4.7% of axial thrust were also achieved at reduced e ciency. The side force ampli cation factors were independent of operating nozzle pressure ratio for the range of chamber pressures used in this test series.