• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.9
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• pp.369-374
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• 2016

Cooling towers have been installed on rooftops or outside of buildings and widely applied to control the indoor temperature in residential areas and buildings. However, the noise and vibration resulting from their operation may cause problems in adjacent buildings. The purpose of this study is to measure the noise and vibration of an industrial cooling tower located adjacent to industrial plants and to investigate its influence on the surroundings according to an authorized evaluation standard. Further, in order to measure the effect of the vibration of the tower on the precision equipment inside the plant, an experiment is conducted to measure the vibration of the ground in the plant and the targeted precision equipment. The measurement results indicate that the noise in the cooling tower is 4 to 9 dB(A) higher than the maximum level defined in the standard of 68dB(A). The effect of the vibration of the tower on the precision equipment is comparatively minimal, because that in the supporting frame of the building is weaker than that on the floor where the precision equipment is located. The vibration of the floor on.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.1024-1027
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• 2004

수원 삼성전자 DM연구소(R4) 신축동 6층 옥상에 위치한 냉각탑으로 인해 인근 연구실 및 사무실에 소음 전파 우려가 있어 이에 대한 소음영향 평가를 수행하고 대책을 수립하고자 한다. 이를 위해 연구실에 대한 소음기준을 설정하고 음향해석기법을 이용하여 방음대책 수립 전 후에 대한 소음영향 평가를 수행하였으며, 냉각탑 소음을 줄이기 위한 방음대책안을 제시하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.1020-1023
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• 2004

Recently, Cooling tower are used the necessary element in a residential area and living space on the viewpoint of indoor temperature control. The purpose of this study is to assistance the comfortable environment and economical measures of noise transmission mechanism on tile cooling tower. The results show that noise evaluation interact the main factor of distance reduction and diffraction reduction. Noise criterion apply to the NC level and equivalent transmission loss about already the design of noise reduction.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.227-228
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• 2012

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.8 no.3
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• pp.361-374
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• 1996

In general, a cooling tower has two major noise sources, one is the fan and the other is the falling water. The fan noise is produced by passage of its blades through the air and radiates from the fan stack. Noises from the falling water are caused by splashing and dropping of water cascading over the internal filler of the cooling tower and into the basin and radiate from the louvered face. In this paper, the noise measurements and its frequency analysis are carried out for the locations facing the louvered side and near the fan stack referring the related code and standards in order to study the noise characteristics of the induced-draft cooling tower, especially for the buildings. As a result, it is found that for every doubling of distance from the noise source the noise level decreases by 2~4dBA in the near field with reflect surfaces and decreases by about 6dBA also in the far field without reflect surfaces. As a supplement to the noise measurements, a computer program with simple algorithm is developed in order to estimate the noise level at a distance from the cooling tower, so that the user could apply and modify it for the particular boundary conditions easily.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.221-226
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• 1995

터빈 익렬, 펌프 익차, 원형 냉각탑, 치차 등과 같이 동일한 형상이 원주 방향으로 반복되어 있는 순환 대칭 구조물의 진동특성을 유한 요소법을 사용하여 해석하는 경우에 전체구조를 모델링하는 대신에 구조물을 동일한 형상의 부분구조로 분할하여 부분구조 한개만을 모델링하고 분할된 경계에서 적절한 경계조건을 부과하여 진동해석을 수행함으로서 컴퓨터 기억용량을 절감시키고 계산시간을 단축할 수 있는 방법이 널리 사용되고 있다. Orris and Petyt[1]는 부분구조의 양쪽 분할 경계면, 즉 연결 경계상에 있는 절점변위의 상관관계를 복소파동전파식을 이용해서 구하여 부분구조의 감소된 복소강성행렬 및 질량행렬을 만들고 실수부와 허수부를 분리하여 유한요소해석을 수행하는 방법을 제안하였다. 유한요소 프로그램 ANSYS[2]에서는 이와 같은 방법을 사용하고 있다. Thomas[3]는 순회 정규모드를 이용하였고, 참고문헌[4]에서는 순회행렬을 이용하였다. 또한 유한요소 프로그램 MSC/NASTRAN[5]에서는 푸리에 급수를 이용하고 유한요소 절점의 위치 및 변위를 원통 좌표계를 표현하여 순환대칭구조물의 유한요소해석을 수행할 수 있도록 되어있다. 본 논문에서는 순환 대칭구조물의 형상의 주기성과 순환성을 고려하여 이산퓨리에 변환을 이용함으로써 순환대칭구조물의 유한요소진동해석을 체계적으로 저용량의 컴퓨터에서 신속하고 정확하게 수행할 수 있는 방법을 제안하고자 한다.