Issue |
JNWPU
Volume 37, Number 2, April 2019
|
|
---|---|---|
Page(s) | 344 - 353 | |
DOI | https://doi.org/10.1051/jnwpu/20193720344 | |
Published online | 05 August 2019 |
Aerodynamic Layout Designs Using of Microflaps for Flow Control of a Supersonic Finned Projectile
基于突起物流动控制的超声速弹箭气动布局研究
1
No. 203 Research Institute of China Ordnance Industries, Xi’an 710065, China
2
Xi'an Technological University, Xi’an 710021, China
Received:
30
June
2018
In this paper, the flow control system consists of some small microflaps located between the rear fins of the projectile. These microflaps can alter the flow field in the finned region of the projectile resulting in asymmetric pressure distribution and thus producing control forces and moments, furthermore to provide directional control for a supersonic projectile. Due to the small size and high speed characteristics of projectile, which is with fast and valid response characteristics, this flow control system has initially shown excellent potential in terms of supersonic flow control. The CFD simulation used here solves steady-state Reynolds-averaged Navier-Stokes equation with two-equation turbulence model k-ε. Firstly, we investigate the flow mechanism around microflap in supersonic flow, the flow fields around the microflap are complex, involving three-dimensional shock-shock, shock-boundary layer interactions. Secondly, for the microflap and the fin of Basic Finner configuration, the influence of microflap geometric parameters, microflap locations on aerodynamics is obtained and the interference mechanism is explored. Finally, several typical roll and pitch control layouts are described. According to the simulation results and their analysis, some preliminary conclusions can be drawn: by analyzing the flow interference mechanism between microflap and the fin, we find that the separated shocks ahead of the microflap, the bow shocks around microflap, and the trailing-edge wake, have influences on fin's surface pressure; among these factors, the bow shocks are stronger than separated shocks, furthermore it can generate larger high pressure region. Then we find out the aerodynamic characteristics of several typical control layouts at a supersonic speed, Ma=2.5, furthermore, hence nearly 4.8% drag is increase compared with the condition without microflap. As the number of microflaps increasing, the control aerodynamic forces and moments increases almost linearly. With a proper layout of the microflap's location, quick change in the surface pressure distribution can be achieved for rear fins of the projectile, the microflap should be mounted that can increase the high pressure zone, meanwhile, reduce the low pressure zone on the surface of fins, thus modulating the projectile's attitude can be realized.
摘要
流动控制方案是在弹身尾部弹翼之间排布一定数量的微型突起物,突起物的干扰造成了弹翼上压力分布的变化,从而改变作用于弹箭上的气动力和力矩,实现弹箭飞行姿态的改变,针对弹箭尺寸小和飞行速度高的特点,极有可能成为超声速飞行弹箭的一种快速有效控制手段。采用数值求解三维定常雷诺平均Navier-Stokes方程和k-ε两方程湍流模型的CFD方法,首先分析了超声速状态下孤立突起物的绕流场结构,细致揭示了孤立突起物产生的激波/激波干扰、激波/边界层干扰等流场结构;其次针对孤立突起物与单个弹翼的组合体构型,揭示出突起物对弹翼的干扰流场结构,分析了突起物的形状与安装位置对弹翼绕流场及气动力的影响规律;最后针对Basic-Finner弹箭模型,研究了多个突起物组合的俯仰与滚转方向控制的气动布局方案。研究结果表明:在超声速状态下,突起物对弹翼的干扰主要来源于3个方面:突起物前面形成的分离流动所产生的分离激波干扰区,绕突起物产生的三维弓形激波干扰区,以及突起物尾迹干扰区。其中,三维弓形激波干扰区域最大,干扰强度大。最后给出了基于突起物控制的俯仰与滚转方向气动布局方案,在Ma=2.5的状态下,比较了不同数量突起物方案的气动特性。单个突起物的存在,使得全弹的阻力增加约4.8%,随着突起物数量的增加,产生的控制力矩基本线性增加。通过合理布置微型突起物的安装位置,可以使得弹箭尾部弹翼上压力快速改变,突起物安装要尽量增大弹翼上的高压区,与此同时尽量减小低压区的干扰,从而实现超声速飞行弹箭姿态的快速控制。
Key words: microflaps / supersonic flow / flow control mechanism / aerodynamic layouts design / computational fluid dynamics / aerodynamic configurations / Mach number / mesh generation / flow fields / aerodynamic drag
关键字 : 微型突起物 / 超声速流动 / 流动控制机理 / 气动布局设计 / 计算流体力学(CFD)
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