Experimental study on support interference of single support rod via force measurement and PIV
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摘要: 针对FL–51低速风洞单支杆腹撑,为研究和优化其支架干扰特性,在风速为70和50 m/s时,开展了支杆预置角11°时(支杆与模型机身轴线的夹角为79°)的24棱、圆截面和截断翼型截面的三维支杆在飞机巡航与增升构型下的纵、横向两步法支架干扰试验。在预置角11°单支杆腹撑支架干扰特性研究基础上,进一步开展预置角为30°、60°(支杆与模型机身轴线的夹角分别为60°和30°)时24棱、圆截面和截断翼型截面支杆的支架干扰特性风洞试验研究。为进一步分析不同尺寸、截面形状的二维支杆绕流与尾流特性,开展了风洞PIV试验。研究结果表明:翼型支杆纵向支架干扰最优,但在横向恶化;随着最大厚度的增大,翼型支杆的尾涡具有较好的一致性,24棱和圆截面支杆的尾涡则随直径变化存在一定的变化;对于仅进行纵向试验或以纵向试验为重点的风洞试验,支杆宜选择翼型截面或适当截断的翼型截面。Abstract: In order to study and optimize the support interference characteristics for the single support rod in the FL–51 low-speed wind tunnel, the longitudinal and transverse two-step support interference test of the aircraft in cruise and uplift configuration is carried out for the three-dimensional support rods with the cross section of 24 ribbed, round and truncated airfoil at the wind speed of 70, 50 m/s and the support rod pre-deflection angle of 11° (the angle between the support rod and the axis of the model fuselage is 79°). Based on the study of the support interference characteristics of the single support rod at the pre-deflection angle of 11°, the support interference characteristics wind tunnel test of 24 ribbed, round and truncated airfoil support rods was carried out at the pre-deflection angle of 30° and 60° (the angle between the support rod and the axis of the model fuselage is 60° and 30° respectively). For further analyzing the characteristics of two-dimensional support rod flow around and wake characteristics with different sizes and cross section shapes, the wind tunnel PIV test is carried out. The results show that the longitudinal support interference of the airfoil support rod is the best, but it deteriorates in the transverse direction.With the increase of the maximum thickness, the wake vortex of the airfoil support rod has good consistency, and the wake vortex of the 24 ribbed and round cross section support rod varies with diameter. For wind tunnel tests that only conduct longitudinal tests or focus on longitudinal tests, airfoil cross section or truncated airfoil should be selected.
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Key words:
- single support rod /
- support interference /
- cross section shape /
- two-dimensional support rod /
- PIV
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表 1 3种截面三维支杆支架干扰特性测量试验内容
Table 1. Support interference characteristics measurement test contents of three-dimensional support rod with three kinds of cross section
序号 截面形状 迎角α 侧滑角β 构型 风速/(m·s−1) 1 24 棱(最大厚度80 mm) −4°~20° 0 后襟:0°/30° 50/70 0°/4°/8° −18°~18° 2 圆截面(直径80 mm) −4°~20° 0 后襟:0° 50/70 0°/4°/8° −18°~18° 3 截断翼型(最大厚度80 mm) −4°~20° 0 后襟:0°/30° 50/70 0°/4°/8° −18°~18° 表 2 3种截面三维支杆不同预置角支架干扰特性测量试验内容
Table 2. Support interference characteristics measurement test contents of three-dimensional support rod with three kinds of cross section and different pre-deflection angles
序号 截面形状 迎角α 侧滑角β 构型 风速/(m·s−1) 1 24 棱(最大厚度80 mm) −4°~20° 0 后襟:0°/30°;预置角:11°/30°/60° 50 0°/4°/8° −18°~18° 2 圆截面(直径80 mm) −4°~20° 0 后襟:0°;预置角:11°/30°/60° 50 0°/4°/8° −18°~18° 3 截断翼型(最大厚度80 mm) −4°~20° 0 后襟:0°/30°;预置角:11°/30°/60° 50 0°/4°/8° −18°~18° 表 3 24棱和截断翼型截面支杆不同构型支架干扰差量
Table 3. Support interference difference of 24 ribbed and truncated airfoil support rods with different configurations
ΔCL ΔCD ΔCma ΔCl ΔCnb ΔCC 24 棱 0.005 0.002 0.006 0.001 0.0005 0.002 截断翼型截面 0.001 0.001 0.004 0.003 0.0006 0.001 表 4 24棱和截断翼型截面支杆不同风速支架干扰差量
Table 4. Support interference difference of 24 ribbed and truncated airfoil support rods with different wind speeds
ΔCL ΔCD ΔCm ΔCl ΔCnb ΔCC 巡航状态 24 棱 0.006 0.001 0.007 0.001 0.0006 0.004 截断翼型截面 0.004 0.002 0.002 0.001 0.0005 0.002 30°后襟 24 棱 0.006 0.002 0.005 截断翼型截面 0.004 0.002 0.002 表 5 24棱支杆、圆截面支杆和截断翼型截面支杆预置角11°和60°的支架干扰差量
Table 5. Support interference differences of 24 ribbed support rods,round support rods and truncated airfoil support rods with pre-deflection angles of 11° and 60°
ΔCL ΔCD ΔCma ΔCl ΔCnb ΔCC 24棱 0.006 0.003 0.015 0.001 0.0007 0.003 圆截面 0.007 0.004 0.015 0.001 0.0007 0.005 截断翼型截面 0.003 0.0012 0.002 0.005 0.0003 0.002 表 6 二维支杆绕流与尾流特性PIV试验内容
Table 6. PIV test content of two-dimensional support rod flow around and wake characteristics
序号 截面形状 模型尺度/mm 风速/(m·s−1) 试验时的侧滑角/(°) 试验次数 1 24 棱 直径:50/80/120 10/30/50/70 0/7.5/15 36 2 圆截面 直径:50/80/120 10/30/50/70 0 12 3 翼型截面 最大厚度:50 10/30/50/70 −30/−25/−20/−16/−12/−8/−4/0/8 36 最大厚度:80 10/30/50/70 −16/−8/0 12 4 截断翼型截面 最大厚度:50 10/30/50/70 −30/−16/−8/0/8 20 最大厚度:80 10/30/50/70 −16/−8/0 12 5 截断翼型截面(短10%) 最大厚度:50 10/30/50/70 −30/−16/−8/0/8 20 最大厚度:80 10/30/50/70 −8/0 8 6 截断翼型截面(长10%) 最大厚度:50 10/30/50/70 −30/−16/−8/0/8 20 最大厚度:80 10/30/50/70 −8/0 8 表 7 各截面支杆尾涡区前段的宽度
Table 7. The trailing vortex region's front section width of support rodwith various cross section
序号 截面形状 模型尺度/mm 尾涡区前段
宽度/mm尾涡的相对
尺度/%1 圆截面 直径50 80 160 直径80 110 137.5 2 24 棱 直径50 60 120 直径80 90 112.5 3 翼型截面 最大厚度50 30 60 最大厚度80 30 37.5 4 截断翼型截面 最大厚度50 50 100 最大厚度80 50 62.5 5 截断翼型截面短10% 最大厚度50 55 110 最大厚度80 55 68.8 6 截断翼型截面长10% 最大厚度50 35 70 最大厚度80 35 43.8 注:1.尾涡区前段宽度为在前段某一固定位置处各支杆尾涡区的宽度。
2.尾涡的相对尺度为尾涡区前段宽度与相应支杆直径/最大厚度的百分比。 -
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