The Engine Position Effect on SWB Airplane Aerodynamic Performance

The Blended-Wing-Body (BWB) airplane concept represents a potential revolution in subsonic transport efficiency for large airplanes. Except the Wing-Body blended way, the propulsion airframe integration of BWB airplane also takes a very important role for its good aerodynamic performances. A 300 seating civil BWB aircraft designed by the Airplane Concept Design Institute of Northwestern Polytechnical University, whose engine is podded on pylon located over the wing, after of the aircraft centre-body, is the original model for analysis. Because its body looks like a ship, we also call it Ship-Wing-Body (SWB). The propulsion airframe integration including researches in many areas, in this paper, only the engine’s position effect on the SWB’s aerodynamics is analyzed. The engine is simplified as a Flow-through Nacelle (FTN), and the pylon is deleted from the model to make clear the problem is only the engine position effect. First the effect of FTN at original position on SWB aerodynamic performance is analysed. Then the FTN Position Change Effects on SWB Aerodynamic Performance is analysed. Through the analysis, it could be seen that there are three main aspects of the effect: the high pressure region caused by nacelle’s leading edge stagnation point; the shock wave interface between nacelle and body; and the separation caused by shock wave. These three main aspects are more sensitive along Z-axis than X-axis. Under the influence of these aspects, the lift and drag coefficient of SWB are changed monotonous along X-axis; but along Z-axis, there is a critical position, at this position, the SWB has maximum lift coefficient and minimum drag coefficient.