低雷诺数下双元素翼帆的襟翼几何参数对其推进特性影响研究

Effects of Flap Geometry Parameters on Propulsion Characteristics of Two-Elements Wingsail at Low Reynolds Number

关键词:  双元素翼帆  襟翼偏转角  襟翼旋转轴位置  失速角  数值模拟

Key words:  Two-elements wingsail  Flap deflection angle  Rotating axis position of the flap  Stall angle  Numerical simulation

摘要:

为了研究大型船舶在航行中翼帆对其推进性能的影响规律，建立了一种双元素翼帆模型，并采用雷诺平均N-S方程在定常和非定常工况下对襟翼几何参数变化的模型进行数值仿真。结果表明，双元素翼帆气动特性的改变体现了襟翼旋转轴位置、襟翼偏转角以及缝隙宽度之间的非线性耦合作用。襟翼旋转轴位置的前移实际上是增大了缝隙宽度，进而增加了流过缝隙的流体，避免了主翼尾流的流动分离。然而，襟翼旋转轴位置的前移距离也受到襟翼偏转角的限制，在襟翼偏转角为25°，攻角为6°，当襟翼旋转轴位置由90%前移到85%时，襟翼吸力面发生了大尺度流动分离。襟翼旋转轴位置不宜过于靠前或靠后，当相对缝隙宽度为2.4%时，襟翼旋转轴位置为85%较为合理。

Abstract:

In order to study the effects of the wingsail on the propulsion performance of a large ship， a two-elements wingsail model is established. Then the Reynolds average N-S equation is used to simulate the model with different geometric parameters of flap under steady and unsteady conditions. The results show that the change of aerodynamic characteristics of the two-elements wingsail reflects the nonlinear coupling among the position of the flap rotating axis， the flap deflection angle and the slot width. The forward movement of the flap rotating axis actually increases the gap width. Furthermore， the fluid flowing through the slot increased to avoid the flow separation of the wing wake. However， the forward displacement of the flap rotating axis is also limited by the flap deflection angle. When the deflection angle of the flap is 25° and the angle of attack is 6°， with the rotating axis position of the flap moving forward from 90% to 85%， large-scale flow separation occurs on the flap suction surface. Therefore the rotating axis position of the flap should not be too forward or backward. When the relative slot width is 2.4%， it is more reasonable to set the rotating axis position of the flap is 85%.