考虑转捩点约束的自然层流翼型变弯度设计

Variable Camber Optimization Design of a Natural Laminar Airfoil

在巡航过程中,大型民用航空飞机的飞行状况不断发生变化。随着燃油的消耗,飞机实际巡航升力系数将偏离设计升力系数,使用变弯度技术能够提升飞机在整个巡航段的气动性能。但是,对于自然层流翼型,传统的翼型变弯度设计将会导致自然层流翼型表面转捩点的前移。基于代理模型和遗传算法,提出了针对自然层流翼型的变弯度优化设计方法。结果表明,在巡航范围内的不同升力系数下,随着翼型弯度的变化,翼型表面仍然能够保持一定程度的层流区域,同时整个巡航段中翼型的气动效率得到了提升。

The flight condition of a long-range aircraft varies during cruising. As the consumption of fuel increases,the actual flight lift coefficient deviates from the design point. By applying variable camber design,the aerodynamic performance could be improved over the cruising condition. However,for natural laminar airfoil,the laminar-turbulent transition position highly relies on its geometry. Therefore,applying variable camber design may bring forward the laminar-turbulent transition position. The purpose of this paper is to investigate the effect of camber variation on the airfoil boundary layer. In addition,based on surrogate model and genetic algorithm,this paper proposed a variable camber optimization design method for a natural laminar airfoil. The results indicated that the design method is feasible. Over the cruising range,as camber varies with the lift coefficient,the surface of the airfoil kept a long laminar flow range.Meanwhile,the aerodynamic performance of a natural laminar airfoil was improved over the cruising range.