An improved PTV technique to evaluate the velocity field of non-spherical particles
An improved PTV technique to evaluate the velocity field of non-spherical particles
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DOI：
10.1016/j.powtec.2010.04.032
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发表时间：
2010-08
影响因子：
5.2
通讯作者：
Y. Chung;S. Hsiau;H. Liao;J. Ooi
中科院分区：
文献类型：
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作者：
Y. Chung;S. Hsiau;H. Liao;J. Ooi
近年来，粒子跟踪测速技术（PTV）已被广泛应用于振动床、转鼓和库埃特剪切池等场合，测量颗粒集合体的平动速度场。然而，这种技术尚未被证明能够确定非球形粒子的速度场。本文的目的是发展一种改进的PTV技术来确定非球形粒子的平移和旋转速度。为了证明这种新的PTV技术的可行性，它被用来研究非球形颗粒在振动床中的对流行为。在示范实施例中，研究了通过粘合两个单个POM珠粒而制成的成对POM颗粒。测试示例是单层准2D模型。根据实验结果对振动床中POM颗粒的局部平均速度、局部脉动速度、颗粒温度、脉动速度分布、自扩散系数和无因次对流流量等输运特性进行了评价和讨论。所开发的改进PTV技术被证明有能力更准确地测量非球形颗粒系统的速度场。研究证实了非球形颗粒在振动床中的对流现象，并表明颗粒在振动颗粒床中的旋转是显著的。在这种具有对流现象的颗粒系统中，平均旋转动能约占平均动能的5.4%，在某些局部区域，旋转颗粒温度占颗粒总温度的17%以上。
In recent years, Particle Tracking Velocimetry (PTV) has been extensively used to measure the translational velocity field of granular assemblies in applications such as vibrated beds, rotating drums and Couette shear cells. However, this technique has not yet been shown to be able to determine the velocity field of non-spherical particles. The aim of this paper is to develop an improved PTV technique to determine translational and rotational velocities for non-spherical particles. To prove the feasibility of this new PTV technique, it was employed to investigate the convection behaviour of non-spherical particles in a vibrated bed. In the demonstration example, paired POM particles made by gluing two single POM beads were studied. The test example was a single layer quasi-2D model. The transport properties of the paired POM particles in a vibrated bed, such as local average velocities, local fluctuation velocities, granular temperatures, fluctuation velocity distributions, self-diffusion coefficients and dimensionless convection flow rates, were evaluated from the experimental results and discussed. The developed improved PTV technique is shown to have the ability to measure more accurately the velocity field of non-spherical particulate systems. The study has demonstrated the convection phenomenon of non-spherical particles in a vibrated bed and has shown that particle rotation is significant in the vibrated granular bed. In such a granular system with convection phenomenon, the average rotational kinetic energy constitutes approximately 5.4% of the average kinetic energy and in some local regions the rotational granular temperature amounts to over 17% of the total granular temperature.