The Journal of the Acoustical Society of Korea (한국음향학회지)

The Acoustical Society of Korea (한국음향학회)
권호 표지

A Study on Determining the Transmission Loss of Water-Borne Noise Silencer in a Sea-Connected Piping System

해수연결 배관계 소음감소기의 투과손실 측정에 관한 연구

  • Published : 2007.08.31
Download PDF
⟨ Previous Next ⟩

Abstract

The dominant source of noise in a sea-connected piping system is usually due to a seawater cooling pump which circulates seawater to operate onboard equipments normally, and so its water-borne noise with some tonal frequencies should be reduced using proper silencers. In order to obtain the transmission loss of water-borne noise silencers experimentally the present paper suggests a transfer function technique that acoustic wave in the piping system is decomposed into its incident and transmitted components when the reflection at the termination of the system exists. Good agreement in the interested frequency range with theory and the proposed technique shows the validity of the technique.

해수연결 배관계에서 발생되는 주요한 소음원은 함 내부 탑재장비의 원활한 작동을 위해 해수를 순환시키는 해수순환 펌프이다. 이러한 펌프에서 발생되는 토널 성분을 가지는 유체전달 소음은 적절한 소음감소기를 통해서 감소되어야 한다. 본 논문에서는 실험적으로 유체전달 소음감소기의 음향 투과손실을 측정하기 위해서 해수연결 배관계의 끝단 반사가 존재하는 경우 배관 내의 음파를 입사파와 투과파로 분리하는 전달함수 기법을 제안하였다. 제작된 소음감소기 시험시편에 대한 이론적 투과손실과 제안된 기법을 통해 측정된 투과손실이 관심 주파수 영역에서 잘 일치함을 확인함으로써 기법의 타당성을 검증하였다.

Keywords

References

  1. M. L. Munjal, Acoustics of Duct and Mufflers (John Wiley & Sons, New York, 1987), Chap.2, pp, 55-60
  2. P. M. Morce and K. U. Ingard. Theoretical Acoustics (McGraw-Hill. New York, 1968), Chap.9. pp, 467-471
  3. ASTM C384-03, 'Standard Test Method of Impedance and Absorption of Acoustic materials by the Impedance Tube Method' American Society for Testing and Materials, 2004
  4. W. S. Gatley and R. Cohen, 'Methods for evaluating the performance of small acoustic filters,' J. Acoust. Soc. Am. 46, 6-16, 1969 https://doi.org/10.1121/1.1911661
  5. M. M. Louden, 'The single pulse method for measuring the transmission characteristics of acoustic system,' Acoustica 25, 167-172, 1971
  6. R. Singh and T. Katra, 'Development of an impulse technique of measurement of muffler characteristics,' J. Sound and Vib. 56, 279-298, 1978 https://doi.org/10.1016/S0022-460X(78)80021-2
  7. A. F. Seybert and D. F. Ross, 'Experimental determination of acoustic properties using a two-microphone random excitation technique,' J. Acoust. Soc. Am. 61. 1362-1370, 1977 https://doi.org/10.1121/1.381403
  8. D. A. Blaser and J. Y. Chung, 'A transfer function technique for determining the acoustic characteristics of duct systems with flow,' Inter-noise 78. 907-913. 1978
  9. J. Y. Chung and D. A. Blaser, 'Transfer function method of measuring in-duct acoustic properties. I. Theory,' J. Acoust. Soc. Am 68. 907-913. 1980 https://doi.org/10.1121/1.384778
  10. ASTM E1050-98, 'Standard Test Method for Impedance and Absorption of Acoustic Materials Using A Tube, Two microphone and A Digital Frequency Analysis System' American Society for Testing and Materials, 1998
  11. S. H. Jang and J. G. Ih, 'On the multiple microphone method of measuring in-duct acoustic properites in the presence of mean flow,' J. Acoust. Soc. Am. 103, 1520-1526, 1997 https://doi.org/10.1121/1.421289
  12. Conesco, Study of Fluid-borne Noise and the Development of Fluid Acoustic Filter Test Specifications and Design Rules, (Conesco, Inc., 1964)