• Title/Summary/Keyword: Ultrasonic Standing-wave

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Generating a Traveling Wave on an Annular Ring (원환판에서의 진행파 구현 실험)

  • Yun, Shin-Il;Cho, Ji-Hyun;Han, Sang-Bo
    • Proceedings of the KSME Conference
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    • 2001.06b
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    • pp.607-612
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    • 2001
  • Rotary ultrasonic motors are based on the traveling wave generated by piezo materials attached on the stator. Large scale model of an annular ring was built to understand the fundamental mechanism involved in the rotary ultrasonic motors. 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.

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Finite Element Analysis of a Particle Manipulation System Using Ultrasonic Standing Wave (정재초음파를 이용한 입자제어 시스템의 유한요소해석)

  • Cho, Seung-Hyun;Park, Jae-Ha;Ahn, Bong-Young;Kim, Ki-Bok
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.20 no.1
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    • pp.3-9
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    • 2010
  • Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.

Finite Element Analysis of a Particle Manipulation System Using Ultrasonic Standing Wave (정재초음파를 이용한 입자제어 시스템의 유한요소해석)

  • Cho, Seung-Hyun;Park, Jae-Ha;Ahn, Bong-Young;Kim, Ki-Bok
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2009.04a
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    • pp.565-570
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    • 2009
  • Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, an adaptive layer, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.

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Agitation Effects of an Ultrasonic Standing Wave on the Dynamic Behavior of Methane/Air Premixed Flame (메탄/공기 예혼합화염의 동역학적 거동과 정상초음파의 교반)

  • Seo, Hang-Seok;Lee, Sang-Shin;Kim, Jeong-Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.3
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    • pp.16-23
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    • 2012
  • This study has been conducted to scrutinize agitation effects of an ultrasonic standing wave on the dynamic behavior of methane/air premixed flame. The propagating flame was caught by high-speed Schlieren images, through which local flame velocities of the moving front were analyzed in unprecedent detail. It is revealed that the propagation velocity agitated by the ultrasonic standing wave is greater than that without agitation at the stoichiometric ratio: the velocity enhancement diminishes as the equivalence ratio approaches upper flammability limit or lower flammability limit. Also, vertical locations of the wave-affected frontal distortions do not vary appreciably, unless the propagating-mode characteristics (pressure amplitude and driving frequency) of ultrasonic standing wave were not changed.

Propagation Behavior and Structural Variation of C3H8-Air Premixed Flame with Frequency Change in Ultrasonic Standing Wave (정상초음파의 주파수 변화에 따른 C3H8-Air 예혼합화염의 전파거동 및 구조변이)

  • Lee, Sang Shin;Seo, Hang Seok;Kim, Jeong Soo
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.38 no.2
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    • pp.173-181
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    • 2014
  • The propagation behavior and structural variation of a premixed propane/air flame with frequency change in an ultrasonic standing wave at various equivalence ratios were experimentally investigated using Schlieren photography and pressure measurement. The propagating flame was observed in high-speed Schlieren images, allowing local flame velocities of the moving front to be analyzed in detail. The study reveals that the distorted flame front and horizontal splitting in the burnt zone are due to the ultrasonic standing wave. Vertical locations of the distortion and horizontal stripes are intimately dependent on the frequency of the ultrasonic standing wave. In addition, the propagation velocity of the flame front bounded by the standing wave is greater than that of the flame front without acoustic excitation. As expected, the influence of the ultrasonic standing wave on premixed-flame propagation becomes more prominent as the frequency increases.

Interacting Effects of an Ultrasonic Standing-wave on the Propagation Behavior and Structural Stabilization of Propane/Air Premixed Flame (프로판/공기 예혼합화염의 전파거동 및 구조안정화에 대한 정상초음파의 간섭효과)

  • Lee, Sang Shin;Seo, Hang Seok;Kim, Jeong Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.6
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    • pp.1-8
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    • 2012
  • An experimental study has been conducted to scrutinize into the influence of ultrasonic standing wave on the propagating behavior and structural stabilization of propane/air premixed flame at various equivalence ratios in half-open rectangular duct. Evolutionary features of the flame fronts are caught by high-speed images, and the variation of flame structure and local flame velocities along the propagation are analyzed. It is revealed that the propagation velocity agitated by the ultrasonic standing wave is greater than that without the agitation: the velocity enhancement diminishes as the equivalence ratio approaches the stoichiometric. Influence of standing wave on the flame overwhelms that of the buoyancy which slants the flame front towards top of the duct, and thus the standing wave contributes to the structural stabilization of propane/air premixed flame.

Effects of the Equivalence Ratio on Propagation Characteristics of CH4-Air Premixed Flame Intervened by an Ultrasonic Standing Wave (정상초음파가 개재하는 CH4-Air 예혼합화염의 전파특성에 대한 당량비의 영향)

  • Seo, Hang Seok;Lee, Sang Shin;Kim, Jeong Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.2
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    • pp.16-23
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    • 2013
  • An experimental study has been conducted to investigate the effects of equivalence ratio on the propagation characteristics of $CH_4$-air premixed flame intervened by an ultrasonic standing wave. A Schlieren photography was used for the flame structure visualization, and the flame propagation behavior was investigated in detail throughout the post-processing analysis. It is found that the structural variation of methane/air premixed flame caused by the intervention of ultrasonic standing wave give rise to the enhancement of combustion reaction and flame propagation velocity. Effectiveness of the standing wave on the flame velocity decreases as the equivalence ratio increases. Larger flame velocity with the standing wave becomes undistinguishable in a specific range of equivalence ratios.

Agitation Effects of an Ultrasonic Standing Wave on the Dynamic Behavior of Methane/Air Premixed Flame (메탄/공기 예혼합화염의 동역학적 거동에 대한 정상초음파의 교반 효과)

  • Seo, Hang-Seok;Lee, Sang-Shin;Kim, Jeong-Soo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2012.05a
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    • pp.318-323
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    • 2012
  • This study is conducted to scrutinize agitation effects of an ultrasonic standing wave on the dynamic behavior of methane/air premixed flame. The propagating flame is caught by high-speed schlieren images, through which flame front and local flame velocity are analyzed and obtained, too. It is revealed that the propagation velocity with ultrasonic standing wave is larger than the case without excitation except around the flammability limits. Also, vertical locations of distortions and depth of dents of the front are constant, unless the ultrasonic standing wave characteristics are not changed.

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Behavioral Change of the Ultrasonic Standing Wave-affected Flame in the Reaction Zone of the Ultrasonically-atomized Kerosene Injected through a Slit-jet Nozzle (Slit-jet 노즐을 통해 분사되는 초음파 무화 케로신 화염의 정상초음파 가진에 의한 거동 변이)

  • Bae, Chang Han;Kang, Yun Hyeong;Ahn, Hyun Jong;Kim, Jeong Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.1
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    • pp.60-67
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    • 2022
  • A study was conducted to analyze the behavioral change of the kerosene flame ultrasonically-atomized under an ultrasonic standing-wave. Combustion region was visualized through DSLR, ICCD camera and the Schlieren photography with high-speed camera. The fuel consumption was measured by a precise scale. As a result, in the case of ultrasonic standing-wave excitation, it was observed that the intensity of OH radical(OH*) was enhanced and optimal combustion condition was formed around the upper edge of the standing-wave field.

Combustion Characteristics According to the Equivalence Ratio of Hydrocarbon Fuel/Air Premixture Excited by Ultrasonic Standing Wave (정상초음파가 인가된 탄화수소계 연료/공기 혼합물의 당량비에 따른 연소특성)

  • Kim, Min Cheol;Bae, Seong Hun;Hong, Joon Yeol;Kim, Jeong Soo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.628-631
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    • 2017
  • An experimental study of the combustion characteristics according to the equivalence ratio of hydrocarbon fuel/air premixture excited by ultrasonic standing wave are presented. The image of the propagating flame was acquired using a high-speed camera, and the combustion characteristics of each fuel were closely observed through image processing. it was conformed that ultrasonic standing wave has been found to stimulate the combustion reaction in the stoichiometric ratio.

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