EXTENDING FLOW CONTROL OF FIXED NOZZLES THROUGH SYSTEMATIC DESIGN: INTRODUCING ASSISTED REINJECTION

摘要

Under Wright Laboratory’s (WL) Fluidic Injection NozzleTechnology (FLINT) contract, Lockheed Martin TacticalAircraft Systems (LMTAS) conducted a systematic Design ofExperiments (DOE) investigation of fluidically-controlled,fixed-geometry nozzles using Computational Fluid Dynamics.Using a fractional-factorial design approach, a fixed nozzleconcept was identified that varied effective throat area byinjecting secondary air at the nozzle throat and routing nozzlecore air around the geometric throat to be “reinjected” into thecore stream. This “assisted reinjection” concept represents asignificant advancement in nozzle flow control, allowing throatarea to increase 50% using only 10% injector mass flow ratio.The impact of non-circular aperture shapes (e.g. elliptical, 2D,triangular, and plug) and discrete injection on fluidic nozzleperformance was also quantified. These results will help WLand LMTAS develop durable, signature-oriented exhaustsystems that provide additional aircraft flight capability whiledramatically reducing system weight and cost.