叶栅表面微形貌的气动特性影响机理与减阻方法研究

发布时间：2018-01-28 12:11

本文关键词： 凹坑面减阻特性粗糙度叶片气动性能数值模拟风洞实验　出处：《大连理工大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着航空业的快速发展,现代飞机高速、高燃油率等对航空发动机性能提出了极高的要求。压气机叶片作为航空发动机核心组件之一,其气动特性的优劣直接决定着发动机性能的好坏。因此,研究叶片表面微形貌对其气动特性的影响规律,及如何降低叶片总压流动损失,提高叶片气动性能,是当前主要任务。本文首先设计一种新的凹坑结构并采用数值模拟的方法研究其在湍流流场中的流动特性,并考虑凹坑形状、直径、深度、间距和排布等对流动特性的影响规律,选出减阻性能最佳的组合方式；随后通过分析凹坑面和光滑面的壁面切应力、静压、近壁区流场特征及流动参数沿高度方向的变化等研究凹坑面湍流流动特性及机理。然后将减阻性能最佳的凹坑结构应用在叶片上,并分别布置在吸力面30%-60%和75%-95%倍轴向弦长处,研究凹坑对不同攻角下叶栅气动特性的影响规律,并比较两者的减阻性能；并对凹坑叶片表面静压系数、粘性阻力、尾迹损失、总压流动损失等气动参数的变化作深入的分析。数值研究结果表明：凹坑有效地降低了叶片流动损失；随后对叶片表面凹坑的减阻特性进行风洞实验验证,证实了将凹坑应用于航空叶片表面的可行性。最后针对航空叶片加工精度问题,采用可实现化k-ε湍流模型和可展壁面函数法,研究叶片表面粗糙度大小和分布对不同攻角下叶片气动性能的影响规律。选取七种粗糙度值(等效砂砾粗糙度Ks=4.96、9.92、19.84、39.06、77.5、155、2001μm),和三种粗糙度分布(将吸力面平均分成前(0-1/3c),中(1/3-2/3c),后(2/3-1c)三部分),并对叶片吸力面粘性阻力、尾迹损失、总压流动损失、负载能力等气动参数的变化作深入分析。研究结果表明,粗糙度存在一个阂值,小于该阈值时,对叶片总压流动损失影响不大,超过阈值时,总压流动损失将急剧增加；另外,叶片吸力面整体粗糙效应远大于局部粗糙效应；叶片局部粗糙时,所有攻角下,叶片吸力面前、中部(0-2/3c)粗糙对叶片气动性能影响较大,吸力面后部(2/3-lc)粗糙对叶片气动性能的影响较小。最后进行平面叶栅风洞实验,所得实验结果与数值仿真结果趋势基本一致。
[Abstract]:With the rapid development of the aviation industry, modern aircraft speed, high fuel rate put forward high requirements to the engine performance. The compressor blade as one of the core components of aero engine, its aerodynamic characteristics directly determines the performance of the engine. Therefore, the influence of blade surface topography on aerodynamic characteristics. And how to reduce the blade total pressure flow loss, improve the aerodynamic performance of the blade, is the main task. This paper designs a new pit structure and Research on dynamic characteristics of the turbulent flow in the flow by the method of numerical simulation, and consider the pit shape, diameter, depth, spacing and arrangement influences on flow characteristics the selected combination of the best performance of the drag reduction; followed by analysis of the pit surface and smooth surface of the wall shear stress, static pressure, near wall flow characteristics and flow parameters along the height direction Flow characteristics and mechanism of the change of surface pit turbulence. Then drag the best performance of the pit structure used in the leaves, and are arranged on the suction surface of the 30%-60% and 75%-95% double axial chord, influence of dynamic characteristics of cascade under different attack angle of pits, and compare the drag reduction performance; and the static pressure coefficient of the blade surface pits, viscous resistance, wake total pressure loss, change of flow loss and other aerodynamic parameters are deeply analyzed. The numerical results show that pits can effectively reduce the flow loss of leaves; then the drag reduction characteristics of concave surface of the blade by the wind tunnel experiment, confirmed the feasibility of application of pits on blade the surface. Finally, aiming at the problem of machining accuracy can be achieved by using air blade, k- turbulence model and wall function method can show, on the leaf surface roughness of different size and distribution Influence of blade angle of attack performance. Selecting seven kinds of roughness (equivalent sand roughness Ks=4.96,9.92,19.84,39.06,77.51552001 mu m), and three kinds of roughness distribution (the average suction surface is divided into (0-1/3c), in (1/3-2/3c), (2/3-1c) after the three part), and on the blade suction surface viscous resistance wake total pressure loss, flow loss, changes in load capacity and other aerodynamic parameters are analyzed. The results show that the roughness of the existence of a threshold value is less than the threshold value, has little effect on the blade total pressure flow loss exceeds the threshold, the total pressure loss of flow will increase dramatically; in addition, the blade suction surface integral roughness effect is far greater than the local roughness effect; blade local roughness, all angles of attack, the blade suction front, central (0-2/3c) rough blade on the aerodynamic performance of the large rear part of the suction surface (2/ 3-lc) rough effect on blade aerodynamic performance is In the end, a plane cascade wind tunnel experiment is carried out. The experimental results are in good agreement with the numerical simulation results.

【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：V231.3

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