Relationship between the geometric characteristics of the polished area and the key parameters of the flow field creation
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摘要: 磁流变抛光在其实际工作过程中,抛光区域几何特征的不同将会对流场创成的关键参数产生很大的影响。针对此问题建立三维模型与实验仿真展开研究。在研究抛光区域几何特征与流场创成关键参数的关系时,先改变抛光区域形状,观察其对流场创成中剪切应力、压力产生的影响;再控制抛光区域的形状相同时,通过改变抛光区域尺寸大小,观察对流场创成中剪切应力、压力产生的影响。结果表明:当抛光区域形状不同时,抛光区域为凹面时剪切应力最大,抛光区域为凸面时剪切应力最小。当抛光区域形状为凸面时,抛光区域两边的剪切应力随着抛光区域曲率大小增大而增大;当抛光区域形状为凹面,抛光区域两边的剪切应力随着抛光区域曲率大小增大而减小。当抛光区域形状不同时,抛光区域为凹面时压力最大,抛光区域为凸面时压力最小。当抛光区域形状为凸面时,抛光区域处的压力随着抛光区域曲率增大而增大;当抛光区域形状为凹面时,抛光区域处的压力随着抛光区域曲率增大而减小。Abstract: In the actual working process of magnetorheological polishing, the difference of the geometric characteristics of the polished area will have a great influence on the key parameters of the flow field creation. However, there is still a lack of research in this area, so this article establishes a three-dimensional model and experimental simulation for this problem. In studying the relationship between the geometric characteristics of the polished area and the key parameters of the flow field creation, first change the shape of the polished area to observe its influence on the shear stress and pressure in the flow field creation; when the shape of the polished area is the same, change the size of the polished area and observe its effect on the shear stress and pressure in the creation of the flow field. It is found that when the shape of the polished area differs, the shear stress is the largest when the polishing area is concave, while it is the smallest when the polished area is convex. When the polished area is convex, the shear stress on both sides of the polished area increases as the curvature of the polished area increases; when the polished area is concave, the shear stress on both sides of the polished area increases as the curvature of the polished area increases. When the shape of the polished area is different, the pressure is maximum when the polished area is concave, and the pressure is minimum when the polished area is convex. When the shape of the polished area is convex, the pressure at the polished area increases as the curvature of the polished area increases; when the shape of the polished area is concave, the pressure at the polished area decreases as the curvature of the polished area increases.
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表 1 选用的磁流变抛光工艺参数
Table 1. Selected magnetorheological polishing process parameters
consistency index,
k/(sn−2/m)power law
indexyield stress
threshold ptemporary shear
rate/(1/s)flow coefficient
nribbon
thickness/mmribbon
width/mmpolishing wheel
speed v/(m/s)inlet and outlet
pressure/Pa59.01 0.7301 13861.84 100 0.3755 1.5 15 4.71 101000 表 2 不同形状抛光区域
Table 2. Polished areas of different shapes
No. immersion depth h/mm shape 1 1.0 concave 2 1.0 convex 3 1.0 plane 表 3 选取的抛光区域曲率大小参数
Table 3. Curvature parameters of the selected polishing area
No. immersion
depth h/mmconvex
curvature r/mmconcave
curvature r/mm1 1.0 80 180 2 1.0 120 210 3 1.0 160 240 4 1.0 200 270 5 1.0 240 300 6 1.0 280 330 7 1.0 320 360 8 1.0 360 390 9 1.0 400 420 10 1.0 440 450 表 4 不同形状抛光区域
Table 4. Polished areas of different shapes
No. immersion depth h/mm shape 1 1.0 concave 2 1.0 convex 3 1.0 plane 表 5 选取的抛光区域曲率大小参数
Table 5. Curvature parameters of the selected polishing area
No. immersion
depth h/mmconvex
curvature r/mmconcave
curvature r/mm1 1.0 80 180 2 1.0 120 210 3 1.0 160 240 4 1.0 200 270 5 1.0 240 300 6 1.0 280 330 7 1.0 320 360 8 1.0 360 390 9 1.0 400 420 10 1.0 440 450 -
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