• 한국산학기술학회논문지
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• 제14권1호
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• pp.51-56
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• 2013

본 논문은 철도 차량에 사용하는 라인 플로우 팬의 소음 저감을 위해 소음원을 규명하여 저감하는 실험적인 연구이다. 라인 플로우 팬의 소음은 공기 유동에 의한 난류성 유동 및 랜덤성 소음, 블레이드 통과 주파수(681Hz)의 소음, 모터 회전에 의한 로터의 불균형(28.4Hz)의 구조물 진동에 의한 소음 등 여러 요인에 의해 발생된다. 각각의 소음원에 대해 대책을 수립하여 하우징 가이드 각도 및 거리 조정, 유동 통로의 형상 변경, 로터 밸런싱을 통해 총 5.7dB(A)의 소음을 저감하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.203-206
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• 2001

The reduction of chopping noise generated from inverter compressor and the piping design reducing vibration are the most important items in the quality of air conditioner. The chopping noise is identified by the study of the relationship between carrier frequency and natural frequency of the compressor shell. The high carrier frequency is the key factor in reduction of carrier noise. To keep the natural frequencies of the system as far as away from the operating frequencies appears to be the most important factor in the design of piping system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 춘계학술대회논문집
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• pp.973-978
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• 2003

Vibration and Noise of air conditioner are entirely determined by compressor vibration. Compressor vibration transmitted to the enclosure of air conditioner or Pipes connected compressor with heat exchanger. Enclosure generated noise and vibration. Therefore, the analysis of compressor vibration analysis is considered significant technical issue. For the reduction of vibration of compressor, it is necessary to grasp correctly vibration transmission paths and excitation sources in the compressor shell. Because, shell (Surface of compressor) shows whole vibration characteristic of compressor mechanism. In this paper, vibration intensity was applied to measure vibration energy flow on the shell. From this technique, it is possible to catch the path of vibration propagation along the one cycle and the location of vibration energy sources may change with time on the shell.

• 대한기계학회논문집A
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• 제30권2호
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• pp.202-209
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• 2006

As the economic power is improved and the customer's demand is hard to please, the noise and vibration is the most important yardstick that can determine the quality of the product. Especially, as the airconditioner's demand increase suddenly, the product of quality and the noise is becoming a decisive factor of determining whether purchase the product or not. Therefore, every manufactory is investing a lot of money and research to cut down the unpleasantness induced from noise and vibration. And they are emphasizing their product's difference by advertising a silence very actively. With these reason, the demand of a silent indoor air-conditioner is the essential research filed when the product is develop(:d. In this study, the noise and vibration is visualized in the space and frequency domain by using experimental methods such as operational deflection shape (ODS), modal testing and sound intensity. Also the location of noise source and its characteristic is analyzed in an acoustical point of view to reduce the structure borne noise that come from the fan motor, and the pertinent control method is suggested. Furthermore, the most suitable shape of the motor bracket is suggested by applying FEM and DOE (Design of experiments) in the noise and vibration point a view.

• 대한기계학회논문집
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• 제16권5호
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• pp.999-1003
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• 1992

본 연구에서는 Fig.1에 보인 바와 같이 원심휀이 부착된 실내 에어콘을 대상 으로 하여 원심휀의 진동.소음 특성을 연구하였다. Fig.2에서 보인바와 같이 원심휀 은 전기 모터 축에 커플링 되어 있으며 원심휀의 회전으로 발생된 공기유동은 연결된 덕트 시스템(duct system)을 통해 외부로 방출 된다. 이와 같은 송풍시스템에서 발 생하는 진동.소음은 크게 구조물 진동에 의한 구조물진동소음과 공기유동 자체에서 발 생하는 공기유동소음으로 구별된다. 본 연구는 실험적 연구를 통하여 이들 진동. 소 음원의 주파수 특성과 전체 소음에의 기여도 등을 규명하였다.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2009년도 하계학술발표대회 논문집
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• pp.853-856
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• 2009

Test models which have geometrical similarities with a real room air conditioner (RAC) have been manufactured including visualization windows so that a laser beam can pass through a cross flow fan. Then, flow distributions of the RAC have been investigated using a visualization technique such as a Particle Image Velocimetry (PIV) to analyze an efficiency and noise of the RAC. Pitot tubes have also been used to measure the flow velocity inside the RAC with various positions to confirm the measurement accuracy of the PIV technique. The measured flow velocities have been analyzed and new designs of the RAC have been proposed to improve the efficiency and to reduce the noise for the RAC in this study.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2713-2717
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• 2008

Whole flow fields of a room air conditioner (RAC) have been visualized by a Particle Image Velocimetry (PIV) technique to analyze the flow structure with various inlet and outlet angles, and to control an eccentric vortex which affects an efficiency and noise of the RAC. A test model with 5 stages of a cross flow fan has been manufactured and a transparent acryl has been installed at the side of the test model for the PIV experiment. The inlet and outlet flows and the flow inside the cross flow fan have been analyzed by varying the inlet grill angles and outlet blade angles. The movement of the eccentric vortex has been investigated experimentally by developing the measurement technique for the inner flow field of the cross flow fan. From the visualization of the inner flows, the origins of the noise inside the RAC and the condensation points around the outlet parts of the cold air have been observed and the solution of the problems can be proposed in this study.

• 한국유체기계학회 논문집
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• 제8권2호
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• pp.23-30
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• 2005

The rotary compressor is widely used in the air conditioner because it is efficient and compact. Recently, the need for silent and efficient compressors is much stronger than the past. The new type muffler was invented to reduce the noise level and to improve the efficiency. The new type muffler that has two side discharge holes and dome shape resulted in much lower overall noise level, especially noise levels around 1kHz than the old type one of one center discharge hole in the acoustic spectra. Also it showed a higher efficiency of air conditioner by lowering oil discharging amount of a compressor than old type one of a rectangular shape and two side discharge holes. The noise reduction and efficiency improvement by the new type muffler were verified by tests for votary compressors and air conditioners.

• 한국소음진동공학회논문집
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• 제16권5호
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• pp.551-558
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• 2006

Noise from air-conditioner system installed in the ceiling of a classroom was evaluated to investigate the sound quality of air-conditioning noise. Harmonics of air-conditioning noise were removed and the sound pressure levels of the frequency bands from $250{\sim}630Hz$ were changed to control sound quality. Evaluation for refreshing sensation was conducted using a paired comparison method and the results showed that noise without harmonics were preferred to noise with harmonics. The noises which have larger level increases to the unchanged noise at $250{\sim}630Hz$ were evaluated better in both of the noises with and without harmonics. Results of multiple regression analysis on psychoacoustic parameters and subjective preferences showed sharpness as a major affecting factor in describing the refreshing aspect of air-conditioning sound.

• 한국음향학회지
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• 제43권1호
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• pp.122-130
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• 2024

에어컨 실외기 내부의 압축기 진동 소음은 실외기에서 발생하는 소음의 주 원인으로 인식되고 있었다. 하지만, 압축기의 작동 속도가 증가함에 따라 압축기에 연결된 배관계에서의 냉매 유동 기인 진동에 의한 소음의 상대적 기여도가 증가하였다. 본 논문에서는 에어컨 압축기 배기 배관계에서의 유체 기인 소음을 수치적으로 예측할 수 있는 해석방법을 정립하였다. 이 단계에서, 해석 결과와 실험결과의 비교를 통해 해석의 신뢰성을 확인하였다. 추가적으로, 압축기 배기 배관계 방사 소음에 대하여 압축기 맥동음과 압축기 진동에 의한 소음의 영향을 주파수 대역별로 비교하였다. 압축기 진동에 의한 소음이 저주파수 대역에 기여함을 확인하였으며, 압축기 맥동음이 고주파수에서의 소음에 영향을 줌을 확인하였다.