论文部分内容阅读
翼梢小翼能抑制翼尖涡流形成、降低机翼的诱导阻力,翼梢小翼的高度是对减阻效果影响较大的参数之一。传统翼梢小翼仅针对巡航状态设计,而在起降、爬升等非设计状态减阻效果不佳。变体翼梢小翼能根据飞行状态主动改变几何外形和尺寸,实时优化减阻效果。为了实现变形,设计了一种用于变体翼梢小翼的伸缩栅格,通过步进电机驱动,可使翼梢小翼的高度主动变化。采用机械系统动力学自动分析软件(ADAMS)研究了伸缩栅格的动力学特性。仿真结果表明:伸缩栅格在970.9N.mm的电机转矩作用下,高度变化率可达13.9%,伸缩周期小于4.4s;模型试验验证了该结果。以飞机起飞阶段的流场特性(马赫数Ma=0.1,迎角α=6°)为例,采用计算流体力学(CFD)与风洞试验相结合的方法,分析了变体翼梢小翼高度的变化对机翼翼尖尾涡流动结构和升阻特性的影响,结果表明:增大翼梢小翼的高度可显著降低翼尖尾涡强度,最大降幅约为47.7%;并可将机翼的升力系数提高3.5%,阻力系数降低4.8%。因此,采用伸缩栅格的变体翼梢小翼具有改善飞机起飞性能的潜力。
Winglets can inhibit the formation of wingtip vortex, reducing the induced resistance of the wing, wingtip height is one of the parameters that greatly affect the drag reduction effect. Traditional wingtip winglets are designed only for cruising conditions, and drag-and-drop and non-design conditions such as climbing do not work well. Variant wingtips can actively alter geometry and size based on the state of flight, optimizing the drag reduction effect in real time. In order to achieve the deformation, a retractable grid is designed for the variant wingtip, which is driven by a stepper motor to actively change the height of the wingtip. The dynamic characteristics of telescopic grids were investigated using Mechanical System Dynamics Automatic Analysis Software (ADAMS). The simulation results show that the telescopic raster can change the height by 13.9% under the motor torque of 970.9N.mm with the telescopic cycle less than 4.4s. The model test verifies this result. Taking the flow field characteristics (Mach number Ma = 0.1 and angle of attack α = 6 °) during take-off phase as an example, CFD and wind tunnel test were used to analyze the variation of winglet winglet height The results show that increasing the height of wingtip can significantly reduce the tip-tailed vortex strength, the maximum decrease is about 47.7%; and the wing Lift coefficient increased by 3.5%, drag coefficient decreased by 4.8%. As a result, a modified winglet with retractable grids has the potential to improve aircraft takeoff performance.