• Title, Summary, Keyword: 다공판 시스템

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An Experimental Study to Develop the Perforated Panel System for Noise Chamber (소음쳄버용 다공판 시스템 개발을 위한 실험적 연구)

  • Lee, Young-Sup;Lee, Dong-Hoon;Chung, Kwang-Seop
    • Journal of the Korean Society for Railway
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    • v.12 no.5
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    • pp.806-810
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    • 2009
  • The air conditioner system that is used in large structure, such as hospital, hotel, railway platform and train generate a high level noise generally. A chamber with sound absorbing materials, such as glass wool and polyurethane foam, are installed in this system to reduce the noise. However, these chambers cause environmental problems owing to the sound absorbing materials recently. Therefore, we develop noise chamber a built-in perforated panel resonance system as eco-friendly chamber to solve this problems. This noise chambers show the same noise reduction performance as the current chambers in the range above 500Hz. But, it reduces the noise up to 8dB(A) comparison to the current chambers in the range 200Hz~400Hz.

Pool Boiling Enhancement of R-123 Using Perforated Plates (다공판을 사용한 R-123 풀비등 열전달 촉진)

  • Kim, Nae-Hyun
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.40 no.5
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    • pp.275-281
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    • 2016
  • In this study, we investigate the pool boiling enhancement caused by perforated plates on top of a smooth surface. We conduct tests using R-123 at atmospheric pressure. It was shown that perforated plates significantly enhanced the pool boiling of the smooth surface. The reason may be attributed to the increased bubble contact area between the plates. The results showed that the enhancement ratio was dependent on the heat flux. At high heat flux, the enhancement ratio increased as the porosity increased. However, at low heat flux, the enhancement ratio decreased as the porosity increased. For the present investigation, the optimum configuration had a pore diameter of 2.0 mm, pore pitch of $2.5mm{\times}5.0mm$ or $5.0mm{\times}5.0mm$, and a gap width of 0.5 mm, which yielded heat-transfer coefficients that are close to those of GEWA-T. The optimum porosity for R-123 was significantly larger than that of water or ethanol. The reason for this may be the large liquid-to-vapor density ratio along with the small latent heat of vaporization of R-123. The perforated plates yielded smaller boiling hysteresis compared with that of the smooth surface.

Numerical Study of Impact for Particulate Matter Reduction Device According to Installation of Perforated Plate and Mixer on Marine Diesel Engine (선박용 디젤엔진의 미세먼지저감 장치에 다공판과 믹서의 장착이 미치는 영향에 대한 수치해석적 연구)

  • Yun, Byoungkyu;Cho, Sanghyun;Ryu, Younghyun
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.25 no.7
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    • pp.968-973
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    • 2019
  • This study presents the characteristics of a pressure drop and uniformity index for a particulate matter reduction device with a perforated plate and mixer for marine diesel engines. The perforated plate and mixer equipped on the particulate matter reduction device induce an increase of exhaust gas reduction performance by increasing the uniformity index. Whereas, the perforated plate induces pressure drop increases in the particulate matter reduction device. Therefore to calculate the effect of the uniformity index and pressure drop of the perforated plates and mixer, this study combines several cases using five types of perforated plates and one type of mixer. Consequently, these results were analyzed to determine the optimized type and position of the perforated plate and mixer.

Noise Reduction of a Ventilating Fan System using Micro-Perforated Panel (미세 다공판을 이용한 환기팬 시스템의 소음저감)

  • Lee, Jong-Seuk;Song, Hwa-Young;Lee, Dong-Hoon;Kwon, Hyuk-Jung;Kim, Dong-Yun
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.1209-1211
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    • 2006
  • This paper introduces an experimental study for the noise reduction of a ventilating fan system. For the purpose of noise reduction, conventionally an absorptive duct silencer filled with a glass fiber has been utilized. However, a glass fiber has some disadvantages like hygiene and secondary pollution problems. In order to overcome these problems, in this paper, a perforated duct silencer has been applied to the ventilating fan system. For the designing of a perforated duct silencer, the transmission losses for various perforated panel systems are measured and compared with its noise reduction performance.

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A Study on the Sound Absorption of Multiple Layer Perforated Plate Systems Combined with Porous Absorbing Materials (다공성 흡음재가 조합된 다중 다공판 시스템의 흡음성능에 관한 연구)

  • Heo, Sung-Wook;Kim, Wook;Lee, Dong-Hoon;Kwon, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.896-901
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    • 2002
  • The sound absorption coefficients for multiple layer perforated plate systems containing several compartments with airspaces and porous absorbing materials are estimated using the transfer matrix method developed in the previous paper. The absorption coefficients from transfer matrix method agree well with the values measured by the two-microphone impedance tube method for various combinations of perforated plates, airspaces or porous materials. Based on these results, a guidance for the design of multiple layer perforated plate systems combined with airspaces and porous absorbing materials is discussed in detail.

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A Study on the Sound Absorption of Multiple Layer Perforated Plate Systems Combined with Porous absorbing Materials (다공성 흡음재가 조합된 다중 다공판 시스템의 흡음성능에 관한 연구)

  • Heo, Sung-Wook;Lee, Dong-Hoon;Kim, Wook;Kwon, Young-Pil
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • pp.388.1-388
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    • 2002
  • The sound absorption coefficients for multiple layer perforated plate systems containing several companments with airspaces and porous absorbing materials are estimated using the transfer matrix method developed in the previous paper. The absorption coefficients from transfer matrix method agree well with the values measured by the two-microphone impedance tube method fur various combinations of perforated Plates, airspaces or porous materials. (omitted)

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A Study on the Improvement of Acoustic Absorption of Multiple Layer Perforated Panel Systems (다중 다공판 시스템의 흡음성능 향상에 관한 연구)

  • Lee, Dong-Hoon;Seo, Seong-Won;Hong, Byung-Kuk;Song, Hwa-Young
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.5
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    • pp.571-577
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    • 2005
  • The acoustic absorption of multiple layer perforated panel systems is largely reduced at the anti-resonance frequency. In order to improve the acoustic absorption at the anti-resonance frequency, the sound absorbing materials are inserted between perforated panels. By the insertion of absorbing materials, it is found that the multiple layer perforated panel system has better acoustic absorption at the anti-resonance frequency and more broadband frequency. Besides, it is shown that the absorption coefficients from the transfer matrix method agree well with the values measured by the two-microphone impedance tube method for various combinations of perforated panels, airspaces or sound absorbing materials.

A Study on the Sound Absorptive Characteristics and Performance of Parallel Perforated Plate Systems (병렬 다공판 시스템의 흡음특성과 성능에 관한 연구)

  • Hong, Byung-Kuk;Song, Hwa-Young;Seo, Seong-Won;Lee, Dong-Hoon
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • v.15 no.9
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    • pp.1003-1008
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    • 2005
  • The acoustic absorption of a multiple layer perforated plate system is very good near the resonance frequency region, while it has been regarded as a demerit that its frequency bandwidth is considerably narrow. In order to overcome such a demerit, the parallel perforated plates with different porosities are proposed. The sound absorption of such system composed of a parallel perforated plate is calculated by an equivalent electroatoustic circuit approach and validated by comparing the calculated absorption coefficients with those measured by the two-microphone impedance tube method. The sound absorptive characteristics and performance of parallel perforated plate systems are discussed from a standpoint of frequency bandwidth related with sound absorption.

Experimental Study on Solar Air Collector with Perforated Endothermic Panels (흡열 다공판을 이용한 공기식 태양열 집열 유닛에 관한 연구)

  • Kim, Myoung-Jun
    • Journal of the Korean Society of Marine Engineering
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    • v.34 no.4
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    • pp.455-459
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    • 2010
  • In recent years, the crisis of energy is growing seriously and also the contamination of ecology has been reverberated as international problem. The social concerns on energy crisis have been growing for the last several years and also the interests in new and renewable energy have been increased. Therefore, in order to solving these problems, this study has dealt with the solar air collector with perforated endothermic panel to increase the indoor temperature. And also, the PV panel for running indoor air circulating fan has used to increase the convective heat transfer. From this study, the inlet air temperature is increased up to 42[$^{\circ}C$]. This temperature is enough to heat the indoor air condition during winter season. And also the result revealed that the mixing effect of convection is increased with increasing in fan circulating power.