• 제목/요약/키워드: Combustion Vibration

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A study on the reduction of noise and vibration by acoustic resonance in the tube bank of a circulating fluidized bed combustion boiler (순환 유동층 보일러 관군의 음향공진에 의한 이상소음 발생 및 저감 연구)

  • Park, Eung-Kyu;Song, Keun-Bok;Kim, Won-Hyun;Joo, Won-Ho
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2011.10a
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    • pp.101-106
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    • 2011
  • In the present paper, the phenomena of abnormal noise and vibration due to acoustic resonance of CFBC(Circulating Fluidized Bed Combustion) boiler was presented. The acoustic resonance which occurred in the gas path of CFBC boiler system was caused by coincidence of vortex shedding frequency of tube bank and acoustic natural frequency of duct and hopper. And, the phenomena of beating arose from the interference of two closed resonant waves at 66.4Hz and 70.8Hz. There are two control methods for acoustic resonance in this system. The first method is to change the vortex shedding frequency from the structural alterations on the tube bank. And the second method is to change the acoustic natural frequency of the gas path with the installation of anti-noise baffles. The second one which is relatively easy to apply, was adapted in this study. As a result, the noise and vibration level have been decreased by 41dB and 94% at 66.4Hz, respectively. And the improvement of noise and vibration at 70.8Hz was identified by sensory evaluation.

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Active Control Method of Heat-Duct Coupled Noise in a Cylindrical Combustor (원통형 연소기에서의 열-덕트 연성 소음의 능동 제어 연구)

  • 조상연;이용석;엄승신;이수갑
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 1998.04a
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    • pp.678-683
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    • 1998
  • Combustion instability by thermoacoustic feedback incite strong low frequency noise and vibration which damage the system and provoke the environmental problems. Therefore, it is necessary to control the thermoacoustic oscillation. In the way of controlling the instability, active control method using adaptive algorithm is applied. In this study, active noise control method using anti-sound technique is selected, whose principle is cancelling the noise with the addition of opposite phase sound. At first, simulation is performed to confirm the stability of controller, and after that control of combustion instability is carried out to get cancellation of 20-30dB SPL.

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The Effects of an Abnormal Adjusting Intake and Exhaust Valves on the Combustion Characteristics of SI Engine (흡.배기 밸브의 밀착이상이 엔진연소특성에 미치는 영향)

  • Park Kyoung-Suk;Son Sung-Man
    • Journal of the Korean Society for Precision Engineering
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    • v.22 no.3 s.168
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    • pp.123-129
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    • 2005
  • The unbalance of the power output, noise, and vibration is happened by the disproportionate pressure variation in the cylinder. For this reason, decrease of the pressure in the cylinder and increase of the residual gas effect on the engine performance. If the abnormal combustion is continued, the crack would be occurred in the engine block. And it could be broken down. For the normal combustion of the SI engine, it is important to supply the balanced mixture by each operating condition. In this study, it was tested the combustion characteristics in the cylinder according to the abnormal adjusting of intake & exhaust valve. This test is willing to set a basic data's analysis fur developing an automotive diagnosis system by analyzing the pressure in the cylinder, the output signal of MAP sensor, the exhaust gas, etc.

Diesel Combustion Noise Reduction based on the Numerical Simulation (디젤 엔진소음 II)

  • 강종민;안기환;조우흠;권몽주
    • Journal of KSNVE
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    • v.7 no.6
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    • pp.909-918
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    • 1997
  • Combustion oriented noise is a part of engine noise, which is mainly determined by the in-cylinder pressure profile and the structure attenuation of an engine. A numerical model for predicting the in-cylinder pressure profile and the resultant combustion noise developed by the use of a commercial code. The model is experimentally validated and updated based on the performance as well as the noise by considering the fuel injection timing, the fuel injection rate, Cetane number, intake temperature, and compression ratio. For providing a design guide of a fuel injector for a low combustion noise engine model, the optimal parameters of injection pressure profile, injection rate profile, and injection timing are determined, which gives the 5 dBA noise reduction.

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Experimental Noise Separation of a Diesel Engine (디젤 엔진소음 (1) ; 실험적 소음 분리기법)

  • 강종민;안기환;박해성;조우흠
    • Journal of KSNVE
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    • v.7 no.5
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    • pp.757-764
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    • 1997
  • The well-developed noise separatrion techniques are applied to the V8 RG8 Diesel engine for the engine noise reduction of a commercial vehicle. For various loads and engine RPM's, the contribution of the combustion oriented noise and the mechanically induced noise was calculated under the small variations of the injection timing. For the given Diesel engine the mechanical noise is dominant for low rpm, and the contribution of the combustion noise becomes greater as the rpm increases. The combustion noise is dominant around 2kHz range or under 50% loading condition.

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Experience Cases of Combustion Instability in Development of Gas Generator for Liquid Rocket Engine (액체로켓엔진 가스발생기 개발에서의 연소불안정 경험 사례)

  • Kim, Munki;Lim, Byoungjik;Kim, Seong-Ku;Kim, Jong-Gyu;Choi, Hwan-Seok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.61-64
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    • 2017
  • The gas-generator open cycle is adapted for liquid rocket engine of Korea Space Launch Vehicle-II. The combustion instability can interfere with combustion performance and cause a noise and vibration or carry the potential for serious damage. This study introduces the experience cases of combustion instability in development of the gas generator for liquid rocket engine.

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Analysis of excitation forces for the prediction of the vehicle interior noise by the powertrain (Powertrain에 의한 차량실내소음 예측을 위한 엔진 가진력 해석에 관한 연구)

  • Lee, Joo-Hyung;Kim, Sung-Jong;Kim, Tae-Yong;Lee, Sang-Kwon
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2006.11a
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    • pp.82-88
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    • 2006
  • The objective of this paper is to get excitation forces of the engine. A powertrain geometry model is produced by CATIA and its FE model is made by MSC/Patran. A vibration mode analysis which makes us know the natural frequency and mode shape and a running mode analysis which measures the mode shape as a relative displacement about one reference point by measuring the acceleration of each bracket to take a place at the running vehicle are experimentally implemented. After getting a satisfied MAC value by doing a correlation about a measured mode analysis value and analyzed value through MSC/Nastran software, all components are assembled through MSC/ADAMS software which is a dynamic analysis tool. We can predict the vibration of brackets which is the last points to occur the force of the engine combustion by analyzing the combustion force produced by engine mechanism.

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