旋翼/机翼气动干扰对复合式直升机性能影响

Influence of rotor/wing aerodynamic interference on performance of compound helicopters

为研究旋翼/机翼气动干扰对双螺旋桨推进复合式直升机的高速飞行性能的影响,建立一种可快速预测复合式直升机飞行性能的模型,以加装机翼和螺旋桨的AS365N“海豚”直升机为样例,分析了400 km/h高速飞行时,旋翼/机翼气动干扰对全机飞行性能的影响及机理,并探讨了用副翼操纵配平气动干扰引起的机翼滚转力矩时,全机功率的变化规律。研究表明:气动干扰增加了机翼的诱导速度,导致机翼的升力系数降低、阻力系数增加。在旋翼不对称涡系的作用下,位于旋翼前行侧下机翼的诱导速度和升阻力系数变化比后行侧的更显著。气动干扰导致机翼升力分配从80.00%降低至71.59%,旋翼升力分配从20.04%增加至28.48%。旋翼、螺旋桨和全机功率分别增加了16.60%、1.86%和3.76%。气动干扰使机翼滚转力矩增加、旋翼滚转力矩减小,利于全机配平,但会增加全机功率。用副翼操纵来平衡由气动干扰引起的机翼滚转力矩时,旋翼侧向周期变距和阻力减小,降低了全机功率。

To investigate the influence of rotor/wing aerodynamic interference on the high-speed flight performance of a dual-propeller propelled compound helicopter,a flight performance prediction model of compound helicopters is established.Taking the AS365N‘Dolphin’helicopter equipped with a wing and propeller as an example,the influence and mechanism of rotor/wing aerodynamic interference on the flight performance are investigated at a high speed of 400 km/h.The change rule of the helicopter power is investigated when the aileron control is utilized to trim the wing rolling moment caused by the aerodynamic interference.The studies indicate that the aerodynamic interference increases the induced velocity of the wing,resulting in a decrease in the lift coefficient and an increase in the drag coefficient of the wing.Due to the asymmetrical vortex of main rotor,the induced velocity,lift and drag coefficients of the wing under the advancing side of the rotor change more significantly than those on the retreating side.Aerodynamic interference decreases the wing lift share from 80.00% to 71.59%,and increases the rotor lift share from 20.04% to 28.48%.The power of the main rotor,propeller and helicopter is increased by 16.60%,1.86% and 3.76% respectively.Aerodynamic interference increases the wing rolling moment and decreases the main rotor rolling moment,which is conducive to the aircraft trim,but is inconducive for the power reduction of the aircraft.When the aileron is utilized to balance the wing rolling moment caused by the aerodynamic interference,the lateral cyclic pitch and drag of main rotor are reduced,and hence the aircraft power is decreased.