仿生非光滑减阻表面的设计制造及减阻技术的若干研究

发布时间：2018-07-03 06:24

本文选题：仿生学 + 减阻　；参考：《沈阳理工大学》2014年硕士论文

【摘要】：近年来，随着能源需求的增加以及对环境保护的要求，如何寻求一种既高效又环保的减阻方法成为各国学者研究的热点问题。本文所做的是仿生学非光滑表面减阻技术的研究，将生物体表面的非光滑结构抽象为凹坑形，并将凹坑单元采用叶序理论进行排布，对叶序排布凹坑表面应用于空气介质的减阻性能进行了研究。本文主要的研究工作如下：分析植物组织的生长特点，得到按照植物叶序生长规律的曲线，应用最小二乘原则将叶序生长规律曲线与旋成体二次曲面的母线方程拟合，得到影响叶序排布方式的相关参数，，结合工程实际，设计出了符合叶序排布规律的凹坑表面。采用ANSYS FLUENT对所选定的旋成体表面不同位置的叶序排布凹坑表面的减阻效果进行了数值模拟计算，仿真结果表明，尾部采用叶序排布凹坑的旋成体表面能够取得更好的减阻效果；在相同的仿真条件下对平行排布的凹坑表面、交错排布凹坑的表面以及按照不同生长系数的叶序排布凹坑表面的减阻效果进行了比较，仿真的结果表明，按照叶序排布的凹坑表面所达到的减阻效果要好于其他两种排布方式的表面；最后，分析了凹坑单元的尺寸对减阻效果的影响，得到了在所选择的旋成体表面布置叶序排布凹坑单元能够减阻的凹坑尺寸范围；最后，通过极差分析法对影响旋成体减阻效果的因素进行分析，得到了具有最佳减阻效果的参数组合，按照该组合排布的旋成体表面达到的最大减阻率达到3.8%。通过对叶序排布凹坑形表面对旋成体近壁区流动的影响可以发现，叶序排布凹坑表面可以使近壁面气体的速度梯度降低，并且由于凹坑内部旋转气流形成的“滚珠轴承”作用的影响，改变了气体与壁面之间的摩擦形式；在相同面积内布置相同数量的不同排布方式的凹坑单元发现，叶序排布的凹坑表面能够起到“滚珠轴承”作用的凹坑数量多；叶序排布凹坑表面无论是在减小摩擦阻力和压差阻力方面，均比平行排布和交错排布方式的凹坑表面有更好的减阻效果。
[Abstract]:In recent years, with the increase of energy demand and the requirements of environmental protection, how to find a high efficiency and environmental protection drag reduction method has become a hot issue for scholars all over the world. In this paper, the bionic non-smooth surface drag reduction technique is studied. The non-smooth structure on the surface of organism is abstracted as a crater, and the pit unit is arranged by the theory of leaf sequence. The drag reduction performance of the surface of the blade arrangement pit applied to the air medium is studied in this paper. The main work of this paper is as follows: the growth characteristics of plant tissue are analyzed, and the curve of plant leaf sequence growth is obtained. By applying the least square principle, the curve of leaf sequence growth law is fitted with the generatrix equation of the conic surface of the rotated body, and the relevant parameters affecting the arrangement of leaf sequence are obtained. Combined with the engineering practice, the concave surface that accords with the arrangement law of leaf sequence is designed. Using ANSYS fluent, the drag reduction effect of different positions of blade arrangement on the surface of rotary body is simulated. The simulation results show that the effect of drag reduction can be achieved better when the rotor surface is arranged by blade sequence. Under the same simulation conditions, the drag reduction effects of parallel arranged concave surface, staggered concave surface and leaf sequence arranged pit surface according to different growth coefficients are compared. The simulation results show that, The drag reduction effect of the pit surface arranged according to the leaf sequence is better than that of the other two arrangement modes. Finally, the effect of the size of the pit unit on the drag reduction effect is analyzed. The size range of the pits arranged on the surface of the rotated adult to reduce the drag is obtained. Finally, the factors that affect the drag reduction effect of the rotary adult are analyzed by means of range analysis. A parameter combination with the best drag reduction effect is obtained, and the maximum drag reduction rate of the rotated adult surface arranged according to the combination is 3.8%. It is found that the velocity gradient of gas near the wall can be decreased by arranging the surface of the pit by the influence of the surface of the leaf sequence arrangement on the flow near the wall of the rotated body, and it is found that the surface of the pit can decrease the velocity gradient of the gas near the wall. And because of the effect of the "ball bearing" formed by the rotating airflow inside the pit, the friction between the gas and the wall is changed, and the same number of pit units with different arrangement are found in the same area. The surface of the pit arranged by the leaf sequence can play the role of "ball bearing" in a large number of pits, and the surface of the pit can be arranged in order to reduce the friction resistance and the differential pressure resistance. Compared with parallel arrangement and staggered arrangement, the pit surface has better drag reduction effect.
【学位授予单位】：沈阳理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB17

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