Design of a Parametric Nozzle for Fluidic Thrust Vectoring Experiments

Andrew John Stagg

Abstract


The fluidic thrust vectoring experimental apparatus at the Australian Defence Force Academy was improved in order for meaningful research to be conducted in the future. This was accomplished by the design of a parametric nozzle and by the installation of new instruments. The new nozzle design allows variation in nozzle geometry and avoids errors in force measurement typical of the old nozzle, by positioning the secondary flow hose axial to the primary flow instead of transverse. The instruments installed were mass flow meters on the primary and secondary lines and a fast acting solenoid valve on the secondary line. The mass flow meters were required to measure flow directly in order to avoid error associated with using the assumption of isentropic flow. The fast acting solenoid valve was installed for transient response experiments where rapid and repeatable flow switching is required. Preliminary experiments were conducted incorporating the new instrumentation. The first experiment compared mass flow in the primary line measured by the mass flow meter, to mass flow calculated using the isentropic assumption. It was found that real mass flow is approximately 65% of isentropic. The second experiment tested the response time of the primary flow to injection of secondary flow. Response times of 20 ms to starting injection and 125 ms to stopping injection were recorded.

Keywords


Thrust vectoring; nozzle; shock vector control

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