摘要
目的分析飞机表面展向三角沟槽微结构的减阻机理,通过参数优化提升其减阻效果,并验证典型飞行条件下的可用性。方法基于RANS k-ε模型开展微流场数值模拟,量化不同马赫数下展向沟槽对摩擦阻力、压差阻力、总阻力的影响;以沟槽深度、顶角、分布密度为变量进行减阻效果的多参数优化;采用模具热压工艺制备沟槽薄膜,并与翼型复合,在FL-3连续流三声速风洞试验平台上系统开展对比试验研究。结果模拟结果显示,沟槽通过诱导微涡流降低沟槽区壁面剪切率,从而使摩擦阻力下降;由于迎/背风边缘压力不对称,会产生额外压差阻力,使其在低速下减阻而高速下反而增阻;参数优化结果表明,在沟槽深度20µm、顶角120°、分布密度1∶2条件下,能有效降低压差阻力系数,获得更好的减阻效果;基于优化后的沟槽参数,采用风洞测得0.35、0.45、0.6、0.8、0.9马赫数下,减阻表面相对于光滑面的减阻率依次为6.35%、4.32%、1.26%、4.60%、4.00%。结论展向三角沟槽在亚音速条件下可通过降低表面摩擦阻力实现减阻效果,通过参数优化能够有效缓解由沟槽前后压力不对称引起的附加压差阻力,提升综合减阻性能;在超音速条件下,压差阻力成为总阻力增长的主要来源,将降低沟槽减阻效果,需进一步优化沟槽结构,以扩展速度适用范围。
Reducing frictional drag on aircraft surfaces has significant implications for enhancing aerodynamic efficiency and reducing fuel consumption.The work aims to systematically investigate the drag-reduction mechanism of spanwise triangular groove microstructures and focus on the optimization of groove geometric parameters to enhance their effectiveness.Previous studies primarily revealed the fundamental drag-reducing and drag-increasing mechanisms of these microstructures,but did not comprehensively investigate the specific effect of groove geometric parameters,or propose optimization strategies validated by experimental data.In contrast,this research extends earlier investigations by thoroughly exploring the effects of critical parameters,including groove depth,apex angle,and groove density,on frictional and pressure drag interactions.To explore the underlying mechanism,numerical simulations of the micro-scale flow fields around the spanwise triangular grooves were conducted with the Reynolds-Averaged Navier-Stokes(RANS)equations combined with the k-εturbulence model.The simulations focused on evaluating the effect of groove microstructures on frictional drag,pressure drag,and total drag at various Mach numbers ranging from subsonic to supersonic conditions.The numerical results revealed that,at subsonic speed,the triangular groove microstructure induced stable micro-scale vortices within the grooves,significantly reducing the local shear rates at the wall surface,thus effectively decreasing frictional drag.However,the same microstructure caused an asymmetric pressure distribution within each groove,forming a distinct high-pressure region at the windward edge and a corresponding low-pressure region at the leeward edge.This asymmetry introduced additional pressure drag,which became increasingly significant as the Mach number rose to supersonic speed,ultimately outweighing the frictional drag reduction and causing an increase in total drag under high-speed conditions.A series of parameter optimization studies examined the effects of critical geometric parameters,including groove depth,apex angle,and groove density,on the drag characteristics.Simulation data demonstrated that a specific configuration of these parameters-namely,a groove depth of 20μm,apex angle of 120°,and groove density ratio of 1∶2,achieved an optimized balance between reducing frictional drag and controlling pressure drag increases,thus improving overall drag-reduction effectiveness.To verify the computational findings experimentally,groove micros-tructures based on these optimized parameters were fabricated with a mold hot-pressing technique,resulting in precise microstructural films.These films were then applied onto specially designed wing-section models suitable for testing in the FL-3 continuous-flow trisonic wind tunnel.Experimental assessments of aerodynamic performance were conducted across multiple subsonic speeds(Mach numbers of 0.35,0.45,0.6,0.8,and 0.9).The wind tunnel measurements provided direct evidence of drag reduction when compared to smooth control surfaces.Specifically,drag reduction rates for the grooved surfaces at these Mach numbers were quantified as 6.35%,4.32%,1.26%,4.60%,and 4.00%,respectively.The results clarified the drag-reduction mechanism of spanwise triangular grooves,identifying the relationship between frictional drag reduction and the corresponding increase in pressure drag.The study provides optimized geometric parameters suitable for practical applications,which has been validated through wind tunnel experiments.However,at higher subsonic to supersonic speed,the pressure drag significantly increases,suggesting the necessity of further optimization to enhance performance across a wider range of flight conditions.Further studies are required to optimize groove geometries specifically for reducing the adverse effects of pressure drag at supersonic speed,thus improving the applicability of the triangular groove microstructures across a broader speed range.
作者
唐绮
翁鼎
武壮壮
孙刚
汪家道
马国佳
TANG Qi;WENG Ding;WU Zhuangzhuang;SUN Gang;WANG Jiadao;MA Guojia(Institute of Surface Engineering Technology,AVIC Manufacturing Technology Institute,Beijing 100024,China;Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China)
出处
《表面技术》
北大核心
2025年第23期156-164,共9页
Surface Technology
关键词
功能表面
飞机减阻
展向三角沟槽
数值模拟
参数优化
风洞实验
functional surfaces
aircraft drag reduction
spanwise triangular grooves
numerical simulation
parameter optimization
wind tunnel experiments
