• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2007년도 추계학술대회논문집
• /
• pp.918-922
• /
• 2007

Aero-pulsation noise, generally caused by geometric asymmetry of a rotating device, is considerable source of annoyance in passenger cars using the turbocharged diesel engine. Main source of this noise is the compressor wheel in the turbocharger system, and can be reduced by after-treatment such as silencers, but which may increase the manufacturing cost. More effective solution is to improve the geometric symmetry over all, or to control the quality of components by sorting out inferior ones. The latter is more effective and reasonable than the former in view of manufacturing. So, an appropriate discrimination method should be needed to evaluate aero-pulsation noise level at the production line. In this paper, we introduce the accurate method which can measure the noise level of aeropulsation and also present its evaluation criteria. Besides verifying the reliability of a measurement system - a rig test system -, we analyze the correlation between the results from rig tests and those from vehicle tests. The gage R&R method is carried out to check the repeatability of measurements over 25 samples. From the result, we propose the standard specification which can discriminate inferior products from superior ones on the basis of aero-pulsation noise level.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2009년도 춘계학술대회 논문집
• /
• pp.342-350
• /
• 2009

Fuel cells convert a fuel together with oxygen in a highly efficient electrochemical reaction to electricity and water. Since the electrochemical reaction in the fuel cell stack dose not generate any noise, Fuel cell systems are expected to operated much quieter than combustion engines. However, the tonal noise and the broad band noise caused by a centrifugal compressor and an electric motor cause which is required to feed the ambient air to the cathode of the fuel cell stack with high pressure. In this study, the multi-camber perforated muffler is used to reduce noise. We propose optimized muffler model using an axiomatic design method that optimizes the parameters of perforated muffler while keeping the volume of muffler minimized.

• 한국소음진동공학회논문집
• /
• 제19권11호
• /
• pp.1151-1157
• /
• 2009

Ensuring both product quality and reducing material cost are important issue for the design of the piping system of an air conditioner outdoor unit. This paper describes a shape optimization that achieves mass reduction of an air conditioner piping system while satisfying two design constraints on resonance avoidance and the maximum stress in the pipes. In order to obtain optimized design results with various analysis fields considered simultaneously, an automated multidisciplinary analysis system was constructed using PIAnO v.2.4, a commercial process integration and design optimization(PIDO) tool. As the first step of the automated analysis system, a finite element model is automatically generated corresponding to the specified shape of the pipes using a morphing technique included in HyperMesh. Then, the performance indices representing various design requirements (e.g. natural frequency, maximum stress and pipe mass) are obtained from the finite element analyses using appropriate computer-aided engineering(CAE) tools. A sequential approximate optimization(SAO) method was employed to effectively obtain the optimum design. As a result, the pipe mass was reduced by 18 % compared with that of an initial design while all the constraints were satisfied.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2006년도 춘계학술대회논문집
• /
• pp.1149-1149
• /
• 2006

The leakage characteristic is an important factor in power plant. However, most of power plant have efficiency problem which is occurred leaking between high pressure steam turbine axle and stator. The labyrinth seal which is used between the main turbine axle and stator in the power plant. Because it is able to be non-contact seal and it is minimize clearance to decrease the leakage. But its actual system is too huge to experiment. Therefore, most steam turbine seal performance tests were conducted by air similarity test. This paper described a test facility and program for air similarity test of high pressure steam turbine seal. A test facility has been designed and built to evaluate leakage verification of labyrinth seal. The test facility consist of air compressor, anti-swirl labyrinth seal for 1/3 air similarity model, pressure transducer, air flow measure system, instrumentation and auxiliary system. For evaluation of steam turbine seal performance, the air similarity test of labyrinth seal leakage verification was conducted and we compared experiment data and analysis result.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2003년도 춘계학술대회논문집
• /
• pp.1205-1205
• /
• 2003

Rotary compressors are one of the most important parts of air-conditioners in the industry This device usually has noise problems during the circulation process of the refrigerant and muffler is used for the noise reduction. The acoustic performance of the muffler depends on its shape and its hole locations on the upper surface. Therefore finding the optimum location of the muffler holes is a topic of increasing importance in the compressor industry. In this research the optimization of the muffler hole locations and the importance of the resonator cavity on the lower surface of the muffler in acoustic point of view is studied. At first, the topology optimization for the 2 hole muffler is performed based on a model without resonator cavity by using genetic algorithm. The 2 hole muffler's acoustic analysis and experiment results are matching, however, the optimized model's results are not. By adding the resonator cavity and also by changing the cavity shape, the acoustic analysis and experiment result comparison is Performed for different cavity shapes. The topology optimization of the revised model with cavity is carried out for noise reduction. Finally, the optimized design is produced and tested for validation.

• 한국추진공학회:학술대회논문집
• /
• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
• /
• pp.877-880
• /
• 2017

원심압축기 임펠러의 블레이드는 고속회전과 정상유동 압력에 의한 정적하중이 가해진다. 동시에 임펠러와 디퓨저 베인 간 상호작용에 의해 발생하는 비정상 유동의 공력가진력이 공진조건에서 주기적으로 임펠러를 가진함에 따라 임펠러 블레이드의 고주기피로 파손이 발생할 수 있다. 이에 대한 정밀한 구조응답 예측을 위해 ANSYS를 이용한 비정상 유동 해석과 모드해석을 각기 수행하여 공력가진력과 주요 공진조건을 도출하였다. 이 후 공력-구조를 연계하는 단일방향의 강제진동 해석을 수행하고, 결과들을 토대로 고주기피로에 대한 안전도를 평가하였다.

• 한국소음진동공학회:학술대회논문집
• /
• 한국소음진동공학회 2005년도 추계학술대회논문집
• /
• pp.427-430
• /
• 2005

The quality of various noises generated in the refrigerator is one of the important factors in deciding quality of the product. The main focus of sound control design has been shifted from reduction of sound level to improvement of sound duality for customer's preference. Up to date the purpose of noise control is the minimization of noise level. However despite of gradual decrease of noise level, occasionally the perceptional quality of noise has not been improved. In this paper, the relation between subjective and objective evaluation of sound quality has established and sound quality index is developed using ANN for evaluation of refrigerator's noise of both the starting noise and the stable running noise of compressor. To verify the usefulness of the index, the results in this paper have been compared with those surveyed by Consumer Union in USA.

• 한국가스학회지
• /
• 제28권2호
• /
• pp.93-104
• /
• 2024

산업현장에서 사용되는 회전기기의 원활한 작동 및 수명연장을 위해서는 설비진단이 필수적이다. 다양한 설비진단의 방법 중 진동진단은 다른 진단방법과 비교하여 불평형(unbalance), 축정렬 불량(misalignment), 베어링 결함(bearing fault), 기어 손상(worn gears), 소음(noise), 공진(resonance) 등 대부분의 초기 결함을 발견할 수 있다. 따라서, 진동분석은 산업현장에서 가장 범용적으로 사용되는 설비진단 방법이며, 설비의 상태를 기반으로 관리하는 예지보전(PdM) 기술로 유용하게 활용된다. 하지만, 진동진단 방법은 기준을 근거로 경험에 의존하여 수행되기 때문에 전문가에 의하여 진행된다. 따라서, 기존에 경험에 의존하여 수행하는 진동진단 방법을 지식화된 코드체계로 구축하여 누구나 쉽게 결함을 판단할 수 있는 시스템을 구축하여 설비의 신뢰성 구축에 기여하고자 한다. 진동측정에 대한 ISO-20816 기준을 근거로 알고리즘을 개발하였고, 석유화학공장 압축기, 수소충전소, 산업용 기계 등 다양한 실증현장에서 진동을 측정한 결과와 개발 시스템을 활용하여 분석한 결과를 비교하여 신뢰성을 검증하였다. 개발된 알고리즘을 통하여 산업현장에서 누구나 회전기기의 상태를 진단하고 결함을 조기에 파악하여 정확한 교체시점에 부품을 교체할 수 있는 예측유지보수(PdM)기술에 기여할 수 있다. 나아가, 정유산업시설, 운송, 생산 시설, 항공시설 등 다양한 산업현장에 적용 시 회전기기의 고장으로 인한 유지보수 비용과 다운타임(down time)의 절감에 이바지할수 있를 것으로 기대된다.

• Tribology and Lubricants
• /
• 제14권2호
• /
• pp.75-81
• /
• 1998

Condition monitoring technology was applied for an air compressor lubricating system to achieve a proactive maintenance, which could prevent a catastrophic failure and detect root causes of the conditional failure of the system. For this work, various types of wear monitoring technology were used and compared with the results of vibration and temperature measurements. The Results generally showed that every technology has a limitation to failure detection, and integrated-based condition monitoring should be performed for the best results. In this work, an idea for the implementing integrated wear monitoring was suggested and demonstrated.

• 한국정밀공학회지
• /
• 제24권1호
• /
• pp.37-46
• /
• 2007

The vibration environment essentially companied by vehicle operation on the ground is determined by the shape of road surface, which is called profile. This paper focuses on development of a profile and severity measurement system for unpaved test courses. In general, the profile and severity of unpaved road is an important issue in the reliability of endurance test. In order to measure unpaved road profile and severity, it is necessary to develop a profilometer system. The developed profilometer system is composed of data processing computer, power unit, air compressor and sensors(encoder, vertical gyro and laser displacement) This paper presents the measuring system configuration, measurement principle of road profile and analysis method of road characteristics used at CPG(Changwon Proving Ground) for this purpose.