Aerodynamic design and optimization of the blended wing body aircraft for 250 passengers

According to the requirement of the passenger cabin structural design and conceptual design, it is investigated to obtain a preliminary aerodynamic design project of 250-passenger BWB. The longitudinal aerodynamic performance at cruising and taking-off is acquired by means of the numerical solution of N-S equations. The solution demonstrates that the highest lift/drag ratio (K_max) is about 15.9 at α=2° at cruising. An aerodynamically optimized design aiming at minimizing drag based on the twist distribution is processed at cruising. Consequently, the contribution of lift is decreased in the outer wing. Wave drag declines while the field of negative pressure in the outer wing becomes narrow. As a result, the lift-to-drag ratio at cruising speed (K_cruise) is increased. Kmax is increased from 15.9 to 20.7. K_cruise is increased from 15.4 to 19.2, approaching to the existing equivalent conventional aircraft. The aerodynamic characteristic of the optimized design at taking-off is improved. And the pitch moment of the aerodynamically optimized design at cruising decreases, that is an improvement considering manipulating.