• Title/Summary/Keyword: Ultrasonic Standing-wave

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Investigation of standing wave acoustic levitation with Bernoulli principle and bolt-clamped Langevin type ultrasonic transducer (베르누이 원리와 bolt-clamped Langevin type 초음파 진동자를 이용한 정상파 음파 공중부양의 탐구)

  • Park, Mincheol;Park, Doojae;Kim, Young H.
    • The Journal of the Acoustical Society of Korea
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    • v.37 no.6
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    • pp.422-427
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    • 2018
  • The purpose of this study is to investigate the effect of acoustic radiation force on the standing wave acoustic levitation phenomenon, which is the levitation of small objects near the pressure node of the standing wave, using the Bernoulli principle. The source and scheme of the acoustic radiation force, which is the cause of the levitation, are conceptually explained through comparison with the graph of the acoustic radiation force versus the distance from the transducer. A series of experiments supporting this explanation was performed with a BLT(Bolt-clamped Langevin Type) ultrasonic transducer to confirm that the objects are floating near the pressure nodes and that it satisfies the condition for the standing wave formation when the object is levitating. Furthermore, the vertical alignment of floating objects, which is a characteristic of standing wave acoustic levitation phenomenon, could be explained.

Position Control of Micro Particles in a Fluid Flow Using Ultrasonic Standing Wave (정재초음파를 이용한 유동중 미세 입자 위치 제어)

  • Cho, Seung-Hyun;Seo, Dae-Cheol;Ahn, Bong-Young;Kim, Ki-Bok;Kim, Yong-Il
    • Journal of the Korean Society for Nondestructive Testing
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    • v.28 no.2
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    • pp.131-136
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    • 2008
  • Using ultrasonic standing waves, micro particles submerged or flowing in fluid can be manipulated. Due to acoustic radiation force of ultrasound, particles are forced to move to pressure nodal or antinodal lines. In this work, we propose a method to control the position of micro particle in a flow by adjusting the frequency of the standing wave. To this end, standing wave field generation system including a few millimeter thick micro channel was established using an immersible ultrasonic transducer. The present generation system works valid in a frequency range between 2.0 MHz and 2.5 MHz. We observed the SiC particles in water moved to pressure nodal lines by the standing wave. The effect of the channel thickness and operating frequency was also investigated. Interestingly, it was shown that the operating frequency have a close relation with the location of the pressure nodal line. Consequently, it fan be said that the position of particle movement rail be controlled by adjusting the ultrasound frequency. The maximum range of the controllable position was about 261 micrometers under the given condition. The resulted observations reveal the possibility of various applications of the ultrasonic standing wave to the manipulation of particles submerged in a fluid.

A Behavior of the Ultrasonically-atomized Kerosene Lifted-flame According to the Position of Ultrasonic Standing-wave Field (정상초음파장의 위치에 따른 초음파 무화 케로신 부상화염의 거동)

  • Chang Han Bae;Jeong Soo Kim
    • Journal of the Korean Society of Propulsion Engineers
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    • v.27 no.1
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    • pp.1-8
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    • 2023
  • A study was conducted to scrutinize the behavior of the ultrasonically-atomized kerosene lifted-flame according to the carrier gas flow-rate and position of ultrasonic standing wave (USW). The combustion region of the kerosene-aerosol generated through a slit-jet nozzle was visualized using a DSLR, ICCD, high-speed camera, and Schlieren technique, and the fuel consumption was measured by using a precision balance. As a result, the flame was confined within the region bounded by the USW-field, and the fuel consumption decreased as the position of the USW field increased.

Frequency-Equivalence Ratio Correlation Analysis of Methane-Air Premixed Flame Influenced by Ultrasonic Standing Wave (I) (정상초음파의 영향을 받는 메탄-공기 예혼합화염의 주파수-당량비 상관도 분석(I))

  • Kim, Min Sung;Kim, Jeong Soo;Koo, Jaye;Kwon, Oh Chae
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.4
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    • pp.37-44
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    • 2015
  • An experimental study was performed for the analysis of frequency-equivalence ratio correlation in the methane-air premixed flame influenced by ultrasonic standing wave. Evolutionary features of the propagating flame were caught by high-speed camera, and the variation of flame-behavior including local velocities was investigated in detail using a post-processing analysis of the high-speed images. It was found that propagation-velocity augmentation of the methane-air premixed flame by the intervention of ultrasonic standing wave was made in leaner mixture, but the velocity diminished when the strength of chemical reaction was saturated around the slightly fuel-rich side of stoichiometry.

Generating a Traveling Wave on the simply Supported Beam (단순지지보의 진행파 구현 실험)

  • Park, Sung-Jin;Yun, Shin-Il;Han, Sang-Bo
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2000.11a
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    • pp.661-666
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    • 2000
  • Traveling wave on the structure can be generated by superposing two standing waves. Precise matching of the amplitudes and phase shift between two standing waves in time and space is the key to the success of generating a traveling wave. The principle of generating a traveling wave on the structure is utilized in the construction of linear and rotary type ultrasonic motors. This paper demonstrates experimentally generating a traveling wave on the simply supported beam.

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Estimation and Analysis of Transport Direction according to Traveling Wave in Ultrasonic Transport System (초음파 이송시스템의 진행파에 따른 이송 방향 예측 및 해석)

  • Jeong, Sang-Hwa;Kim, Gwang-Ho;Shin, Sang-Moon
    • Transactions of the Korean Society of Machine Tool Engineers
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    • v.17 no.2
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    • pp.30-37
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    • 2008
  • An object transport system is driven by a conveyor belt system or a magnetic levitation system. It is an indispensable device in many fields and especially it is very important in the factory automation. However, the conventional transport system can damage precision optical components by the contact force and destroy the inner structure of semiconductor by the magnetic field. The new transport system for transporting without damage is required. The ultrasonic transport system is a device that transports objects on the elastic body using ultrasonic wave. In this paper, an object transport system using the ultrasonic wave is developed for transporting precision elements without damage. Traveling waves are generated by the ultrasonic wave generator fixed in both ends of the beam. The traveling wave of the ultrasonic transport system is theoretically analyzed. Transport direction of the object is examined according to phase difference and frequency. The theoretical results are verified by experiments.

Investigation of Transmission Process for Ultrasonic Wave in Wood (목재 내 초음파 전달 경로 구명)

  • Lee, Jun-Jae;Kim, Gwang-Mo;Bae, Mun-Sung
    • Journal of the Korean Wood Science and Technology
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    • v.31 no.2
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    • pp.31-37
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    • 2003
  • Among the nondestructive evaluation (NDE) methods for wood defect detection, ultrasonic wave has been considered as competitive technique in terms of economics and workability. Until now, researches on application of NDE methods for wood have focused mainly on standing tree and logs. Recently, some attempts have been conducted with NDE technique, for evaluation of wooden structural members. However, wooden structural members are different from others (standing tree or log) in various aspects. Expecially when some parts or whole member are covered with other materials, they can't be evaluated appropriately on general NDE methods. For the purpose of development of proper NDE technique for the wooden structural members, the ultrasonic wave transmission process investigated on artificial defect in wood. First, various types of transmission process were assumed, and then the transmission times were predicted respectively. Predicted times were compared with the measured time of ultrasonic wave and then a suitable type of transmission process is determined. In case of the ultrasonic wave doesn't transmit directly due to defect, it is reflected once only at the opposite surface of member, and the path is accord with the line of shortest length.

Design of a optimum structure for Ultrasonic Linear Motor using a travelling wave (진행파를 이용한 직선형 초음파 모터의 최적구조 설계)

  • 김연보;한우석;노용래
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.13 no.4
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    • pp.280-285
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    • 2000
  • The conventional ultrasonic linear motors developed so far utilize a standing wave and are of a pi-type or a hybrid transducer type structure. Traveling wave type bi-direction linear motors have not been developed yet. This paper describes design of a new bi-directional ultrasonic linear motor working by means of a traveling wave. With the finite element method we design and verify validity of the new structure. And we determine its optimal structure size of design variables material and boundary conditions for proper generation of the traveling wave.

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A Schlieren-photographic Visualization of the Methane/Air Premixed Flame Propagating inside a Rectangular Tube Locally-perturbed by an Ultrasonic Standing Wave (국소적 정상초음파장에 의해 교란되어 사각튜브형 연소실 내에서 전파하는 메탄/공기 예혼합화염의 슐리렌기법에 의한 가시화)

  • Kim, Min Sung;Kim, Jeong Soo;Hwang, Yeong Yeun
    • Journal of the Korean Society of Propulsion Engineers
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    • v.18 no.4
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    • pp.43-49
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    • 2014
  • This experimental study has been conducted to scrutinize the effects of an ultrasonic standing wave (USW) on the propagating velocity and structure of methane/air premixed flame. Propagating flame was caught by high-speed Schlieren photography, and the variation of flame-behavior was analyzed in detail. It is revealed that horizontal splitting in burnt zone is resulted by the USW, and the flame propagation velocity is augmented due to the strengthened chemical reaction. Evolutionary feature of the flame perturbed by USW, maintaining a pseudo-symmetry of top and bottom flame-front about the propagation axis tends to be free from buoyancy effect.

Ultrasonic Field Analysis Using a Sound-Ray Method (음선 기법을 이용한 초음파 음장 해석)

  • 문병환;김진오
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1329-1334
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    • 2001
  • This paper deals with the application of a sound-ray method to the analysis of the sound field in an ultrasonic cleaner. In order to include the wave interference phenomenon, the method has been modified to consider the phase of sound rays, The improved algorithm has been implemented by developing a Visual C++ program, The algorithm has been verified by comparing the analysis results of BEM reported earlier. It has been shown that the algorithm can be used to calculate ultrasonic fields in a cleaning- container with an object to be cleaned.

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