Super-Lift and Thrusting Airfoil of Coflow Jet Actuated by Micro-Compressors
Super-Lift and Thrusting Airfoil of Coflow Jet Actuated by Micro-Compressors
复制标题
微型压缩机驱动共流射流超升力推力翼型
DOI：
--
复制
发表时间：
2018
期刊：
影响因子：
--
通讯作者：
B. McBreen
中科院分区：
文献类型：
--
作者：
Gecheng Zha;Yunchao Yang;Yan Ren;B. McBreen
本文对内嵌微型压气机驱动的同向射流主动流动控制翼型进行了风洞实验研究。这是第一次成功地控制CFJ翼型的自包含零净质量通量（ZNMF）系统。这是将CFJ机翼应用于实际航空航天应用的关键一步。此外，本研究首次在实验中证明了CFJ翼型可以实现超升力系数（SLC），其超过了由CLmax = 2π（1 + t/c）定义的势流理论的理论极限。本文研究的CFJ翼型是在NACA 6421翼型的基础上进行改进的，翼型尺寸为0.72 m × 2.1 m（弦×展）。试验了两种翼型，一种具有较大的喷射槽尺寸以获得高巡航效率和低CFJ功耗，另一种具有较小的喷射尺寸以获得起飞/着陆的高CLmax。当雷诺数从208，000变化到691，000时，自由落体速度从大约4.8 m/s变化到16.2 m/s。在4.8m/s的低自由速度下，通过高升力起飞/着陆构型实现了8.6的CLmax。CFJ翼型还产生非常高的推力，推力系数高达约1.0。推力一直保持到40 ° AoA翼型失速，阻力CD =-0.5。由于微型压气机和CFJ翼型是分开设计的，因此它们在实验中不能最佳地一起工作。微型压缩机运行线大大低于设计运行线，严重损害了压缩机效率。未来的微型压气机设计需要与CFJ翼型的工作条件紧密结合，以利用高的压气机效率。
This paper presents the wind tunnel experimental study of coflow jet (CFJ) active flow control airfoils actuated by micro-compressors embedded inside the airfoils. This is the first time that a CFJ airfoil is successfully controlled by the self-contained zero-net mass-flux (ZNMF) system. It is a crucial step to bringing the CFJ airfoil to practical aerospace applications. Furthermore, this study proves for the first time in experiment that a CFJ airfoil can achieve a Super-Lift Coefficient (SLC), which exceeds the theoretical limit of potential flow theory defined by CLmax = 2π(1 + t/c). The CFJ airfoils studied in this research were modified from the NACA 6421 airfoil geometry with a size of 0.72 m × 2.1 m (chord × span). Two airfoils were tested, one with larger injection slot size for high cruise efficiency and low CFJ power consumption, the other with smaller injection size to achieve high CLmax for takeoff/landing. The freestream velocity varies from about 4.8m/s to 16.2m/s while the Reynolds number varies from 208,000 to 691,000. The CLmax of 8.6 is achieved by the high lift takeoff/landing configuration at the low freestream speed of 4.8m/s. The CFJ airfoil also generates very high thrust with the thrust coefficient up to about 1.0. The thrust is maintained up to the airfoil stall at 40◦ AoA with a drag of CD = −0.5. Since the micro-compressors and the CFJ airfoil were designed separately, they do not work optimally together in the experiment. The micro-compressor operating line is substantially lower the the designed operating line with a severe penalty to the compressor efficiency. Future micro-compressor design needs to be tightly incorporated with the CFJ airfoil operating conditions to make use of the high compressor efficiency.