S弯D形矢量喷管参数化设计及气动特性研究

Parametric Design and Aerodynamic Characteristics of Serpentine D-Shaped Vectoring Nozzle

关键词:  垂直/短距起降  S弯D形喷管  参数化设计  气动特性  矢量角

Key words:  Vertical/Short takeoff and landing  Serpentine D-shaped nozzle  Parametric design  Aerodynamic characteristics  Vector angle

摘要:

为了满足战机对垂直/短距起降能力的要求，基于曲率控制方法对具有D形出口的S弯喷管进行参数化设计，进而可实现喷管尾段的大角度偏转。随后对不同偏转角、落压比以及设计参数的S弯D形矢量喷管气动特性进行数值模拟，对比并分析了喷管的气动特性。计算结果显示：无偏转条件下，随着落压比π从1.5增大至3.5，喷管流量系数先增大后平稳，在π=2.5时达到最大值，推力系数先增大后减小，且推力方向为飞行器产生一定的抬头力矩；落压比恒定时，随着偏转角度从0°增大至90°，喷管流量系数、推力系数下降，矢量超前角由负值不断增大至+6°左右；设计参数中预留偏转角对喷管气动性能影响较大，而S弯中心线控制系数对气动性能影响较小。本文提出的S弯D形喷管具有较好的气动性能，小偏转角度下矢量角变化趋势较为一致，亦可通过出口段偏转实现发动机推力的大角度矢量偏转。

Abstract:

A parametric design method of serpentine D-shaped nozzle based on curvature control method is proposed to meet the requirements of vertical / short takeoff and landing capability for fighters. The serpentine D-shaped nozzle with large angle deflection of D-shaped outlet is designed parametrically. The flow phenomenon and mechanism of the nozzle are simulated by CFD method， and then the aerodynamic characteristics of the nozzle under different nozzle pressure ratio， deflection angle and design parameters are compared and analyzed. The calculation results show that under the condition of no deflection， as the nozzle pressure ratio π increases from 1.5 to 3.5， the nozzle discharge coefficient first increases and then becomes stable， and reaches the maximum value when π=2.5， while the thrust coefficient first increases and then decreases. And the thrust direction produces a certain lifting torque for the aircraft. When the nozzle pressure ratio is constant， as the deflection angle increases from 0° to 90°， the nozzle discharge coefficient and thrust coefficient decrease， and the leading vector angle increases from negative value to about +6°. In the design parameters， the reserved deflection angle has great influence on the aerodynamic performance of the nozzle， while the control coefficient of the serpentine centerline has a little influence on the aerodynamic performance. The serpentine D-shaped nozzle proposed in this paper has good aerodynamic performance. The variation trend of vector angle is relatively consistent under small deflection angle. Thus the nozzle can be used to adjust the jet vector direction of the engine by deflecting the outlet section at large deflection angles.