基于超声旋转驱动的微小颗粒的分离
发布时间：2018-10-30 11:26
【摘要】：微/纳颗粒的分离技术在生物、化学、微机械系统等领域有着广泛的应用。传统的微/纳分离方法有过滤、介电泳、磁性分离、光镊子和超声分离等。过滤分离方法不仅有着过滤介质容易堵塞的问题，而且用于微/纳颗粒过滤的薄膜也比较贵，介电泳和磁性分离技术对于颗粒的性质有一定带电和带磁的要求，光镊子一次处理颗粒的量比较少，，而用超声技术就可以避免以上几种方法的不足。 本课题基于胡俊辉教授团队的研究基础之上，提出了一种超声换能器的新结构，它能够驱动微小颗粒旋转并达到分离效果。该超声换能器是由两块铝板夹着两块环形压电陶瓷片用螺栓紧固而成，换能器的下铝板处于弯扭组合振动，用于颗粒的分离。为了激发出这种振动模态，两块压电片极化方向相反放置并加载交流电压。实验中，我们用多普勒激光测振仪测量工作区域的振动情况，所用到的实验颗粒是虾籽、玻璃球和精盐的两两混合物，实验观察是在高速摄像机下进行的。 实验发现，在铝板的工作区域存在有局部的旋转行波，这能够很好地解释颗粒在工作区域的旋转现象。我们还发现在共振频率下颗粒的分离效率最高，并且颗粒的旋转速度和板的振动幅值对分离效率也有影响。在相同时间内的共振条件下，不同混合物的分离效率也是不同的，其中虾籽和玻璃球的混合物分离效果最佳，虾籽和精盐的混合物分离效果其次，玻璃球和精盐的混合物基本不能分离。我们还从理论上分析了影响分离效率的颗粒的特性，发现颗粒的密度，与板的摩擦因素和颗粒的法向变形量对分离效果有影响。 本课题的主要创新点在于提出了一种新的超声换能器的结构，这种结构没有旋转主轴，能够在空气中利用工作板上的局部旋转行波驱动微小颗粒旋转分离。
[Abstract]:The separation technology of micro / nano particles has been widely used in biology, chemistry, micro-mechanical system and so on. Traditional micro / nano separation methods include filtration, dielectric electrophoresis, magnetic separation, optical tweezers and ultrasonic separation. The method of filtration and separation not only has the problem of easy clogging in filtration media, but also the membrane used in micro/ nanocrystalline filtration is more expensive. Dielectric electrophoresis and magnetic separation technology have certain charge and magnetic requirements for the properties of particles. The amount of particles treated by optical tweezers at one time is less, but ultrasonic technique can avoid the shortcomings of these methods. Based on the research of Professor Hu Junhui's team, a new structure of ultrasonic transducer is proposed, which can drive the small particles to rotate and achieve the separation effect. The ultrasonic transducer is made of two aluminum plates clamped with two annular piezoelectric ceramic plates fastened by bolts. The lower aluminum plate of the transducer is in the bending-torsional combined vibration for the separation of particles. In order to excite this vibration mode, two piezoelectric plates are placed in opposite polarization direction and loaded with AC voltage. In the experiment, the vibration of the working area is measured by Doppler laser vibration instrument. The experimental particles are a mixture of shrimp seed, glass ball and refined salt, and the experimental observation is carried out under a high speed camera. It is found that there is a local rotating traveling wave in the working area of aluminum plate, which can explain the phenomenon of particle rotation in the working area. We also find that the separation efficiency of particles is the highest at resonance frequency, and the rotation speed of particles and the vibration amplitude of plate also affect the separation efficiency. At the same time, the separation efficiency of different mixtures is different, among which the mixture of shrimp seed and glass ball is the best, and the mixture of shrimp seed and refined salt is the second. The mixture of glass ball and refined salt can not be separated basically. We also theoretically analyze the characteristics of the particles which affect the separation efficiency. It is found that the density of the particles, the friction factors with the plate and the normal deformation of the particles have influence on the separation efficiency. The main innovation of this paper lies in the structure of a new ultrasonic transducer, which has no rotating spindle and can drive the rotating separation of tiny particles by using the local rotating traveling wave on the working plate in the air.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB552
本文编号：2299867
[Abstract]:The separation technology of micro / nano particles has been widely used in biology, chemistry, micro-mechanical system and so on. Traditional micro / nano separation methods include filtration, dielectric electrophoresis, magnetic separation, optical tweezers and ultrasonic separation. The method of filtration and separation not only has the problem of easy clogging in filtration media, but also the membrane used in micro/ nanocrystalline filtration is more expensive. Dielectric electrophoresis and magnetic separation technology have certain charge and magnetic requirements for the properties of particles. The amount of particles treated by optical tweezers at one time is less, but ultrasonic technique can avoid the shortcomings of these methods. Based on the research of Professor Hu Junhui's team, a new structure of ultrasonic transducer is proposed, which can drive the small particles to rotate and achieve the separation effect. The ultrasonic transducer is made of two aluminum plates clamped with two annular piezoelectric ceramic plates fastened by bolts. The lower aluminum plate of the transducer is in the bending-torsional combined vibration for the separation of particles. In order to excite this vibration mode, two piezoelectric plates are placed in opposite polarization direction and loaded with AC voltage. In the experiment, the vibration of the working area is measured by Doppler laser vibration instrument. The experimental particles are a mixture of shrimp seed, glass ball and refined salt, and the experimental observation is carried out under a high speed camera. It is found that there is a local rotating traveling wave in the working area of aluminum plate, which can explain the phenomenon of particle rotation in the working area. We also find that the separation efficiency of particles is the highest at resonance frequency, and the rotation speed of particles and the vibration amplitude of plate also affect the separation efficiency. At the same time, the separation efficiency of different mixtures is different, among which the mixture of shrimp seed and glass ball is the best, and the mixture of shrimp seed and refined salt is the second. The mixture of glass ball and refined salt can not be separated basically. We also theoretically analyze the characteristics of the particles which affect the separation efficiency. It is found that the density of the particles, the friction factors with the plate and the normal deformation of the particles have influence on the separation efficiency. The main innovation of this paper lies in the structure of a new ultrasonic transducer, which has no rotating spindle and can drive the rotating separation of tiny particles by using the local rotating traveling wave on the working plate in the air.
【学位授予单位】：南京航空航天大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TB552
【参考文献】
相关期刊论文 前3条
1 赵淳生;面向21世纪的超声电机技术[J];中国工程科学;2002年02期
2 狄建科;周明;杨海峰;戴娟;;飞秒激光与生物细胞作用机理及应用[J];激光生物学报;2008年02期
3 许海,赵淳生;直线型超声电机的发展及应用[J];中国机械工程;2003年08期
本文编号：2299867
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