Interference effects of wing-mounted high bypass ratio nacelle with engine power

Numerical simulation method and aerodynamic interference effects of wing-mounted nacelle aircraft were studied. In aspect of numerical simulation, a practical engineering compatible algorithm for the determination of engine intake and exhaust boundary parameters directly from free stream and engine working conditions was developed. Mesh difference arises from geometry inconsistency between powered and unpowered nacelle, which is a confounding factor when estimating power effect, is eliminated via set up a zero-energy-increase exhaust boundary condition. Then, the credibility of numerical simulation result of complex configuration in aircraft design was improved. The numerical simulation results shown that the engine power has two opposite aspects of effects on wing surface pressure, one is that engine ejection speed the flow up and bring the pressure down, the other is that the engine increasesd the pressure near the nuzzle. The numerical simulation result also revealed that engine jet stream can induce severe flow interferences on surface of pylon, duel to the flow acceleration through the convergent-divergent duct that composed of fuselage, wing, nacelle and pylon surface. Extending and thickening the pylon appropriately, a better flow channel and pylon surface curvature distribution could achieved, and then the interference of the jet flow and pylon surface is relieved, the shock in the inner side of the pylon is eliminated.