250座级翼身融合布局客机气动设计与优化

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

结合民机客舱结构设计参数和飞机总体设计参数要求进行气动布局设计,获得250座级翼身融合(BWB)布局客机初步气动设计方案。采用数值求解N-S方程的方法获得该布局在巡航和起飞条件下的纵向气动特性。结果表明,在巡航条件下α=2°时最大升阻比Kmax可达15.9。以固定巡航飞行升力系数下最小化飞行阻力作为目标优化了机翼展向几何扭转角分布。结果表明,优化后外侧机翼的负载减轻,减小了激波强度和波阻,从而提高了巡航升阻比Kcruise。Kmax由初始布局的15.9提高到20.7,Kcruise由初始布局的15.4提高到19.2,与现役同座级客机接近。优化后起飞特性得到改善,巡航平飞时低头力矩减小,Cm0为更接近零的一小负数,利于操纵。

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（Kmax） 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（Kcruise） is increased.Kmax is increased from 15.9 to 20.7.Kcruise 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.