旋翼翼型定常-非定常特性综合优化设计新方法

旋翼翼型对直升机旋翼及全机气动特性有至关重要的影响。结合直升机飞行特性及旋翼工作气动环境,本文提出了一种新的旋翼翼型设计理念,即定常优化设计同非定常设计相结合的方法来开展直升机旋翼专用翼型的优化设计。首先,建立旋翼翼型非定常气动特性的高精度CFD求解方法,以获得旋翼翼型在相应状态下的升力、阻力和力矩等气动参数。其次,针对旋翼翼型优化状态的特点,对于翼型静态优化及动态失速优化分别采用遗传算法和序列二次规划算法。在上述方法建立基础上,首先针对定常状态下的原始翼型(SC1095)进行优化设计,获得一个满足设计要求的静态优化翼型,进一步着重对该翼型在非定常状态下进行优化设计,成功地得到一种新翼型,并具有非常规外观。结果表明,在设计状态下,新翼型在保持良好定常气动特性的同时,明显减弱了动态失速状态下的分离涡,从而显著改善了翼型的动态失速特性。

New Optimization Design Method for Rotor Airfoil Considering Steady-Unsteady Characteristics

The rotor airfoil has i mportant influence on aerodynamic characteristics of helicopter and its rotor. I ncorporating with the flight characters of helicopter and aerodynamic circumstan ce of helicopter rotor, a new design concept of rotor airfoil is proposed, which is the optimization design method considering both steady and unsteady states for helicopter rotor airfoil design. Firstly, the high accuracy CFD method is establish ed to simulate the unsteady aerodynamic characteristics of rotor airfoil. Consid ering the characters of optimization conditionfor rotor airfoil, the genetic alg orithm (GA) and the sequential quadratic programming (SQP) method are employed in stea dy optimization and unsteady optimization process respectively. In order to obta in an initial airfoil, the optimization design is firstly accomplished under ste ady condition. Then the optimization design under unsteady condition is implemen ted to form a new airfoil with unconventional configuration which is suitable as the rotor airfoil. The optimized airfoil has remarkable improvements on dynamic stall characteristics with obviously weakened separated vortex while it maintai ns considerable aerodynamic characteristics of steady condition.