통합 검색 | Korea Science

배춘희;조철환;양경현;박영필
- 한국소음진동공학회:학술대회논문집
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- 한국소음진동공학회 2003년도 춘계학술대회논문집
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- pp.1065-1069
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- 2003
In this paper, Firstly, it is shown that the high vibration and noise source of piping and pump system is the acostic resonance. Secondly, in order to decrese the high vibration and noise of piping and pump system, the acostic mode of piping have been changed and its effectiveness is investigated as applied it at piping system practically.
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이동훈;주경민;김현섭;김희동
- 대한기계학회:학술대회논문집
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- 대한기계학회 2001년도 추계학술대회논문집B
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- pp.640-645
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- 2001
The present study is to investigate the characteristics of the impulse waves discharged from the exit of the convergent and divergent pipes. An experiment is carried out using a shock tube with an open end and is compared to the computation of the axisymmetric, compressible, unsteady Euler equations, which are solved by the second-order total variation diminishing(TVD) scheme. For the computational work, some initial compression waves are assumed inside the pipe so that those are identical to the experimental ones of the shock tube. The results show that the peak pressures of the impulse waves discharged from the exit of convergent and divergent pipes decrease with an increase in the wavelength of the initial compression wave. All of the impulse waves have a strong directivity toward the pipe axis, regardless of the exit type of the pipe employed. The impulse waves discharged from the divergent pipe are stronger than those from the straight pipe, while the impulse waves of the convergent pipe are weaker than those from the straight pipe. It is believed that the convergent pipe can playa role of a passive control to reduce the peak pressure of the impulse wave. The present computations represent the experimented impulse waves with a good accuracy.
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남경훈;박실룡;이덕주;김재욱
- 한국소음진동공학회:학술대회논문집
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- 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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- pp.271-278
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- 1997
The flow of steam through a safety valve vent pipe system in the boiler has been analyzed to provide a design basis of diffuser silencer for attenuating shock-shell and jet noise. Numerical analysis to estimate inner fluid of silencer and noise propagation outside silencer are performed. The distribution curve of fluid information to provide average values about inner fluid of silencer is presented by theoretical analysis.
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김대홍;이성태;김건인
- 한국소음진동공학회:학술대회논문집
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- 한국소음진동공학회 1996년도 추계학술대회논문집; 한국과학기술회관, 8 Nov. 1996
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- pp.56-64
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- 1996
In this paper, the sound radiation level of parts of a O.B. Motor was measured and analyzed by the measurement method using wave-guide reverberation environment. Based on the above measurement results, a noise control was established for engine cover and exhaust silencer and its effects were compared and analyzed. The noise control method increased transmission loss by painting GELNAC on the engine cover and extend exhaust pipe to reach under water.
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전구식;백승철;김희동
- 대한기계학회:학술대회논문집
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- 대한기계학회 2004년도 추계학술대회
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- pp.1617-1622
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- 2004
Two-phase flow of liquid and gas through pipe lines are frequently encountered in nuclear power plant or industrial facility. Pressure waves which can be generated by a valve operation or any other cause in pipe lines propagate through the two-phase flow, often leading to severe noise and vibration problems or fatigue failure of pipe line system. It is of practical importance to predict the propagation characteristics of the pressure waves for the safety design for the pipe line. In the present study, a theoretical analysis is performed to understand the propagation characteristics of a weak shock wave in a bubbly flow. A wave equation is developed using a small perturbation method to analyze the weak shock wave through a bubbly flow with comparably low void fractions. It is known that the elasticity of pipe and void fraction significantly affect the propagation speed of shock wave, but the frequency of relaxation oscillation which is generated behind the shock wave is not strongly influenced by the elasticity of pipe. The present analytical results are in close agreement with existing experimental data.
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