DEFLECTION OF TURBOFAN EXHAUST STREAMS FOR ENHANCED ENGINE NACELLE INTEGRATION/

An analytical and experimental description of how the fan exhaust of a modern turbofan can he deflected into an annular cascade using only r are bleed flow is presented. Thrust reversing, emphasized herein, and/ or vectoring is achieved without the need for fan duct blockers or oth er hardware devices to turn the flow, allowing lighter, less complex, and lower loss exhaust systems for more efficient up-and-away. flight. Two approaches for deflecting fan flow into an annular cascade, using two different models, are described, and test results are discussed. Results of a Euler analysis and its critical relationship with the tes ting are also described, Both methods use injected core now to turn th e fan flow. One method uses an annular air-curtain emanating from an a nnular injection slot located opposite the cascade and the other uses a similar slot in the nozzle throat to force upstream flows into the c ascade. Both approaches are impacted by engine core bleed limits. Inje ctor jet arrangements to meet this requirement while providing adequat e reverse thrust are described; analyses and test results are reviewed .