• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.9 s.102
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• pp.1060-1069
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• 2005

Silencers are engineering devices that are designed to attenuate sound waves propagating in a flowing medium. The muffler type silencer has a series of chambers in parallel or series utilizing the reflection and expansion characteristics of the expansion chambers, sidetubes, branch resonators, and tailpipes to attenuate the sound. To Improve the performance of industrial blower silencer of muffler type which is employed in petrochemical plant, this paper seeks its optimal arrangement of buffs by experimental method and suggests optimal arrangement of buffs. Experimental results show that the optimal one suggested can reduce the noise level as much as 14 dB (or 18 dB(A)) in the laboratory and as much as 4 dB(A) compared to that of the existing silencer on the ground.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.17 no.3
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• pp.128-132
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• 2008

The noise levels and individual employee noise exposure levels within a factory will determine the need for hearing conservation program. The difficulty in not having an effective hearing conservation program is the risk of hearing loss that employees may sustain. In the last few years the claims for hearing loss compensation have grown due to class action litigation brought against the employer and companies that have equipment in the factory alleged to have caused hearing loss. The Blower in the factory generates the noise of 98.3dB(A) in the frequency range of 2,000Hz, which may cause occupational hearing loss. By designing close type enclosures which are made of absorption material, about 24.4dB(A) reduction has been in the factory. It is demonstrated that this kind of enclosures can be effectively used to reduce the noise in the factory.

• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.21 no.1
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• pp.137-143
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• 2012

In this study, it was conducted to design each components of vane damper for industrial flow control fan and the flow rates were analysed by experimental and numerical method. Through environmental test, it could be confirmed that the designed vane damper was appropriate. Also, almost identical results with test could be drawn from numerical method. Finally, flow rates of electric and pneumatic actuator were measured by test. As the results, difference of flow rate according to opening ratio was smaller in pneumatic actuator than that in electric actuator.

• 유체기계공업학회:학술대회논문집
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• 2001.11a
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• pp.30-34
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• 2001

In the present study, we studied the method of predicting the on-design and on-design point performance of axial flow fan with adjustable pitch blades. With the change of stagger angle of axial flow fan with adjustable pitch blade, flow rate and pressure can be changed. Because of this merit adjustable pitch fans are used in many industrial facility. When changing stagger angle or estimating the performance at a wide range of off-design condition, incidence angle changes greatly as the flow rate changes. Therefore, the deviation angle at the blade exit is estimated by the correlation considering the effects of blade design, incidence angle variation. In the loss model, we used known pressure loss model for blade boundary layer and wake, secondary flow, endwall boundary layer and tip leakage flow. The results of modified deviation angle model and experiment were compared for the usefulness of the modified model.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1990.10a
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• pp.9-14
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• 1990

맥동 연소기는 기존의 연속 연소식 연소기에 비하여 높은 열효율, 소형화, 연소과정의 개선, 시동후 점화플러그 및 송풍팬의 불필요, 자력 배기와 장시 간 안전 운전등의 장점들로 인하여 최근 연구대상으로서 주목을 받고 있다. 맥동연소 현상은 1800년경부터 알려졌음에도 불구하고 기본적인 연소메카니 즘 및 기본동작 원리에 대한 미비점 및 높은 소음 등으로 인하여 종래의 연 구는 거의 실험을 통하여 이루어 졌으며 이러한 것들이 현재까지도 맥동 연 소기의 발전에 걸림돌이 되고 있다. 맥동 연소기가 산업용 및 가정용 열기기 로서 사용되기 위하여 진동과 소음의 감소에 대한 엄격한 요구를 만족하지 않으면 안된다. 따라서, 그에 대한 효과적인 방지 설계를 하기 위하여 진동 원과 소음원이 어느 부위에서 전달되어 오는지를 파악하는 것이 중요하다.. 본 연구에서는 맥동연소기의 소음원을 규명하기 위하여 종래에 사용되어 온 주파수 응답함수법과 소음원간에 강한 상관관계가 존재하는 경우에 사용되 는 기여도함수법을 이용하여 다차원 스펙트럼해석법에 의하여 입출력간의 기여관계를 규명하였다.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.91-96
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• 2011

This study aims to analyze the flow characteristics of turbo-fan which is applied to the industrial field. Numerical analysis has been carried out to investigate the pulsation behavior of exhaust air flown out turbo fan by rotating impeller with constant speed. Moving mesh technique is proved as time-accurate solution for the flow inside impeller. As numerical results come within the error range of 1% by comparing with theoretical results, the numerical analysis can be verified. Cutoff angle has large influence on the amplitude of pulsation and the least pulsation of flow can be generated by the cutoff angle of $20^{\circ}$.

• Solar Energy
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• v.19 no.3
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• pp.115-123
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• 1999

An experimental study was carried out to investigate the flow characteristics of a stationary blade for six kinds of measuring angles of attack, $0^{\circ},\;10^{\circ},\;20^{\circ}\;and\;30^{\circ}$ at Reynolds number of $5.8{\times}10^4$. Instant simultaneous velocity vectors around blade were measured by 2-D PIV system where laser-based illumination and two-frame grey-level cross correlation algorithm were adopted. Velocity profiles show uniform approaching flow from the straightening equipment, and experimental results reveal that separation phenomena occur and the separation point moves upstream with increasing angle of attack.

• Journal of the KSME
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• v.33 no.11
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• pp.951-956
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• 1993

우리나라 자동차 공업의 성장과 더불어 자동차용 공조기기 산업도 빠른 속도로 양적인 성장을 하여, 특히 자동차용 공조장치는 1992년 공조 관련 기기 총생산액의 약 40%를 차지했다. 자동 차용 공조장치는 압축기, 열교환기, 송풍팬 등의 주요 요소로 구성되어 있으며 이중에서 열교환 기는 공조 공간인 차실내의 쾌적성 향상, 구성 기기의 에너지 효율 향상등과 밀접한 관계가 있다. 이러한 자동차용 열교환기는 에너지 파동 이후 에너지와 자원의 절약에 대한 사회적인 요구에 부응하여 보다 고성능, 소형화, 경량화를 요구하게 되었다. 최근에는 전세계적으로 지구 환경문 제에 대한 관심이 고조되어 에너지 자원의 효율적인 이용, 환경 보호 등을 포함하는 광범위한 열문제를 고려할 필요가 있게 되었다. 특히 자동차용 열교환기는 산업용이나 가정용 고조 시스 템의 열교환기와는 달리 설치공간의 제약, 부하 변동폭의 증대 등으로 인해 고성능, 소형화가 요구되며 또한 자동차의 연비향상을 목적으로 경량화가 요구됨과 동시에 환경 문제의 발단인 대체 프레온 대응 등 해결해야 할 기술적인 과제가 많다. 이러한 상황을 감안하여 대표적인 자 동차용 열교환기의 기술 동향을 소개하고자 한다.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.5
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• pp.547-552
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• 2010

A modified VIStA (vortex inertial staged air) burner was developed and used in a once-through-type boiler. For safety, the combustion in this burner is of the non-premixed type. An air damper is installed to control the distribution of air to each combustion chamber. The effects of the air-fuel ratio and air distribution on NOx formation were investigated. The newly modified VIStA burner gives NOx reduction effect by maximum 20% in the combustion chamber of a boiler, while it yields more uniform flame than the conventional burner.