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Design of Ultrasound-Field in Liquid in Materials Processing

材料加工中液体超声场的设计

基本信息

批准号：
06650834
负责人：
KUWABARA Mamoru
金额：
$ 1.28万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1994
资助国家：
日本
起止时间：
1994 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-06650834/
关键词：
Ultrasonic Wave Sound Field Standing Wave Natural Convection Inclusion Composite Directional Control 音響学

项目摘要

For an effective utilization of ultrasonic external force in liquid in materials processing, numerical analysis and measurement has been made on the sound field. Under designed standing wave of ultrasound, model experiments have bee carried out on suppression of thermal convection, coagulated separation of suspended particles, and directional control of reinforcing fibers in composite. The results are summarized as follows :(1) A numerical scheme based on the characteristic curve method has been developed to analyze one-dimensional sound field. A close agreement between calculated and analytical fields as well as observed ones indicated validity of the scheme. The scheme allows to analyze transient propagation of a wave to result in a standing wave. (2) A two-dimensional numerical scheme based on the finite difference solution of the wave equation has been developed to cope with more complicated sound field. This method allows to design sound field taking configuration and materials of a vessel, depth and properties of liquid bath, and frequency and arrangement of ultrasonic vibrators into consideration. (3) Water model experiments to investigate the effect of ultrasound on thermal convection showed that heated liquid element can be suppressed around sound nodes. Major ultrasonic force acting on a liquid element could be radiation pressure in low energy density case and a body force due to time-averaged gradient of sound pressure in high energy density case. (4) An experiment showed a possible separation of suspended inclusions from liquid bath after their coagulation in plane-like nodes. (5) An effective ultrasonic method for directional control of reinforcing fine fibers in composite has been newly proposed and results of supporting experiments and its mechanism has been discussed.

为了在物料加工过程中有效地利用液体中的超声外力，对声场进行了数值分析和测量。在设计的超声驻波下，对复合材料中热对流的抑制、悬浮颗粒的凝固分离、增强纤维的定向控制进行了模型实验。结果表明：(1)提出了一种基于特征曲线法的一维声场分析数值格式。计算场与解析场以及观测场的吻合度非常高，表明了该方案的有效性。该方案允许分析波的瞬态传播，从而产生驻波。(2)提出了一种基于波动方程有限差分解的二维数值格式来处理更复杂的声场。该方法允许考虑容器的结构和材料、液浴的深度和性质以及超声波振动器的频率和布置来设计声场。(3)研究超声对热对流影响的水模型实验表明，在声节点附近，被加热的液体元件可以被抑制。在低能量密度情况下，作用在液体元件上的主要超声力可能是辐射压力，在高能量密度情况下，由声压时间平均梯度引起的体力。(4)实验表明，悬浮物在平面状节点中凝固后，有可能从液浴中分离出来。(5)提出了一种有效的超声定向控制增强复合材料中细纤维的方法，并讨论了支撑实验结果及其作用机理。