• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.10
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• pp.756-762
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• 2014

This paper dealt with numerical estimation of the pressure pulsation of the refrigerant in a suction pipe of the compressor. The behavior of the pressure pulsation was assumed to satisfy the wave equation. The boundary conditions and properties of refrigerant are necessary as input data of the simulation. The pulsating pressures at 15 points in a pipe were measured simultaneously from the pressure transducers. From the experimental data, the complex phase speed and impedance at the end of the pipe of the refrigerant were estimated using the signal processing and used as the input conditions of the numerical analysis. A commercial acoustic software was used to solve the behavior of pressure pulsation. The numerical results for the pressure pulsation in a pipe with and without expansion chamber were carried out and compared with those by experiments. Finally, numerical procedure to estimate the pressure pulsation in a pipe was established and verified.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.564-565
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• 2012

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.2
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• pp.153-159
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• 2010

This work focuses on finding a method to reduce the noise of a hermetic reciprocating compressor during start-up using an acoustical analysis. The noise of compressor during start-up, which is a higher level than that of a normal operating condition, has transient and non-stationary characteristics. The acoustical analysis of compressor cavity is performed to find an effective method to reduce the noise level. In the acoustical analysis, the shape variations of frequency response function in the neighborhood of resonances are tested for three parameters: the height of remained oil, the suction position of refrigerant and the position of driving part. As a conclusion of this result, to reduce the emission noise of compressor during start-up, the height of remained oil should be kept at 16 mm, the refrigerant should be sucked at the cross point of nodal lines of X and Y directional cavity modes, and the driving part should be positioned in the center of cavity.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2009.10a
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• pp.682-683
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• 2009

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.84-85
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• 2010

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.04a
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• pp.67-68
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• 2011

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.319-320
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• 2013

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.562-563
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• 2012

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.875-879
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• 2006

Noise reduction has become a major issue of the duct air-conditioners. This paper describes the reduction of noise and vibration of rotational slim duct system. The design of slim duct system is the most important point of noise reduction in terms of the motor of 2f line noise, resonance noise between forced frequency and natural frequency of Sirocco fan, unbalance noise of motor axis and the noise induced refrigerant. The noise of duct system is mainly measured from diffuser and bottom of duct. The optimal design was implemented after measuring the effect of noise and vibration in each part which is composed of duct system. In this paper, experimental results show that the main elements in air-conditioner duct design. These elements are anti-vibration rubber of motor, axis length of motor, rubber coupler, materials of sirocco fan and control method of motor which are the most vital factors in reducing noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.04a
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• pp.254-254
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• 2014

에어컨 실내기는 소비자와 근접해 있는 실내에 설치되며, 필요성에 의해 가동되므로 소비자들의 소음에 대한 반응이 민감하다. 실내기 소음에는 Fan Noise, Cricking Noise, Refringerant Noise 등이 존재한다. 이중 Refringerant Noise 의 경우 Overall Level 은 낮지만 거슬리는 소음이 발행하여 소비자의 가장 큰 불만을 초래한다. Refringerant Noise 에 대해 발생원인 및 해결 방안 측면으로의 연구는 활발히 진행 중이다. 그러나, 소음에 대한 평가 방법에 대한 연구가 이루어지지 않고 있다. 이에 본 연구에서는 에어컨 실내기 Refringerant Noise 을 대상으로 각 소음 별 특성 분석을 수행하였다. 이를 바탕으로 각 소음 별 영향인자를 도출하였다.