• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.05a
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• pp.644-649
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• 2006

This paper presents a robust and superior control performance of a quarter-vehicle electrorheological (ER) suspension system. In order to achieve this goal, a moving sliding mode control algorithm is adopted, and its moving strategy is tuned by fuzzy logic. As a first step, ER damper is designed and manufactured for a passenger vehicle suspension system, and its field-dependent damping force is experimentally evaluated. After formulating the governing equation of motion for the quarter-vehicle ER suspension system, a stable sliding surface and moving algorithm based on fuzzy logic are formulated. The fuzzy moving sliding mode controller is then constructed and experimentally implemented. Control performances of the ER suspension system are evaluated in both time and frequency domains.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.16 no.8 s.113
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• pp.822-829
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• 2006

This paper presents a robust and superior control performance of a quarter-vehicle electrorheological (ER) suspension system. In order to achieve this goal, a moving sliding mode control algorithm is adopted, and its moving strategy is tuned by fuzzy logic. As a first step, ER damper is designed and manufactured for a passenger vehicle suspension system, and its field-dependent damping force is experimentally evaluated. After formulating the governing equation of motion for the quarter-vehicle ER suspension system, a stable sliding surface and moving algorithm based on fuzzy logic are formulated. The fuzzy moving sliding mode controller is then constructed and experimentally implemented. Control performances of the ER suspension system are evaluated in both time and frequency domains.

• Journal of Energy Engineering
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• v.22 no.1
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• pp.28-37
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• 2013

Stirred tank is widely used in various industries for mixing operations and chemical reactions for single- or multi-phase fluid systems. For designing agitator of high performance, quantity data of internal flow characteristics influenced by mixing performance are definitely confirmed but quantity analysis about the transient flow characteristics of complicate structure is recognized as difficult problem in the present. In this study, two models of commercial CFD code Fluent 6.3 used to propose suitable for the tank analysis. Agitation of Stirred tank is analyzed using a mixed model and the flow in the stirred tank is analyzed using a standard k-${\varepsilon}$ model. Multiple reference frame(MRF) and Sliding mesh(SM), the analysis techniques were used For compare a result of CFD with a visualization experiment result, to grasp internal flow and mixing characteristic in stirred tank and to present fundamental analysis method.

• Proceedings of the KAIS Fall Conference
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• 2008.11a
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• pp.184-187
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• 2008

본 논문에서는 유도가열방식을 이용한 과열증기 발생장치를 제안하였다. 발열방식은 외부의 가열코일로부터 특수 합금 발열체에 비접촉 상태로 전자유도 와전류를 구조체에 흐르게 하였다. 인버터는 스위칭주파수 20[kHz]대역에서 작동되는 풀-브릿지 고주파 직렬 부하 공진형이며, LC 공진 설계에서 부하자체를 L로 선정하여 효율을 최대화 하였다. 개발된 장치는 전자유도가열 발열체와 유체이동에 의한 새로운 열교환 방식으로 일체의 연소과정 없이 기체, 액체 및 증발체 등을 상온에서 500[$^{\circ}C$]이상의 고온에 이르기까지 고정도의 가열이 가능하여 작업환경 개선이 가능하다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.5
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• pp.37-43
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• 2003

Parallel computing method is widely used in the computational fluid dynamics for efficient numerical analysis. Nowadays, low cost Linux cluster computers substitute for traditional supercomputers with parallel computing shcemes. The performance of nemerical solvers on an Linux cluster computer is highly dependent not on the performance of processors but on the performance of network devices in the cluster system. In this paper, we investigated the effects of the network devices such as Myrinet2000, gigabit ethernet, and fast ethernet on the performance of the cluster system by using some benchmark programs such as Netpipe, LINPACK, NAS NPB, and MPINS2D Navier-Stokes solvers. Finally, upon this investigation, we will suggest the method for building high performance low cost Linux cluster system in the computational fluid dynamics analysis.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2002.05a
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• pp.85-90
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• 2002

현재 도시폐기물의 열분해용융 소각로의 개발을 위한 연구가 국내외적으로 진행되고 있다. 열분해용융 소각로는 열분해로, 융용로, 연소실 등과 같이 반응을 동반하는 단위 장치 및 공기 공급부 등에서 에너지 및 유체의 이동이 일어나고 있다. 도시폐기물의 열분해용융 소각로의 개발을 위하여, 파일롯(또는 실험용) 플랜트 또는 향후 상업용 플랜트 제작시에 필요한 설계 개념의 도출 및 주요 설계 변수의 영향 분석을 위한 연구가 필수적이라 판단된다.(중략)

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.6
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• pp.528-536
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• 2010

System identification for cylindrical oil dampers is carried out based on a series of dynamic experimental tests and theoretical approach for the analysis of the experimental data. Experimental tests are conducted using a specific hydraulic actuator in the wide frequency range from 10 Hz to 90 Hz. From this study, it is confirmed that control force of the damper is composed of inertia, damping and restoring components. In general, both restoring and damping components are significant and comparable. However, the portion of the inertia components becomes more significant than to be negligible in the high frequency range.

• Journal of computational fluids engineering
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• v.11 no.4 s.35
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• pp.26-31
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• 2006

In the present study, a numerical simulation of the subway carriage fire is performed to determine the more effective operation of Trackway Exhaust System(TES) in underground stations. The four types of possible TES operation (OSUS, OSUE, OEUS and OEUE) is simulated and compared their removal capability of smoke and hot temperature for the carriage fire of 2MW. From the results, the distribution of temperature and smoke concentration is more dependent on the operation of fans located at upper side of the platform than those at lower side. It is also found from the results that for more efficient smoke control, the fans at upper side of the platform should be operated as an exhaust system. Whereas the fans at lower side can be operated as a supply system to aid upper exhaust fans.

• 한국전산유체공학회:학술대회논문집
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• 2008.03b
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• pp.691-694
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• 2008

Spray characteristics of the APU simplex fuel nozzle are investigated. Four flight conditions such as sea level idle, sea level max power, 20,000 feet idle, 20,000 feet max power are used as spray experimental conditions. Spray visualization was performed by using ND-YAG laser. Droplet size and velocity were measured by using PDPA(Phase Doppler Particle Analyzer) system. From the test result, SMD is 100 ${\mu}$m�� and velocity is 10 m/s at 20,000 ft idle condition. In this condition, flame unstability could be occurred due to the higher drop diameter. Therefore it is necessary to decrease the droplet diameter in the high altitude condition.

• The KSFM Journal of Fluid Machinery
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• v.11 no.3
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• pp.50-55
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• 2008

The diverter system is a key component in achieving a high accuracy liquid flow rate standard using a static gravimetric system with a flying start and stop method. The diverter is a moving device used to direct flow alternately along its normal course(by pass) or towards the weighing tank. The time needed for collection into the weighing tank is measured using a timer. So it is important to the diversion period is sufficiently fast and triggering point of timer which is determined the filling time. On this studies show that uncertainty of diverter system for changing diversion speed and triggering point was estimated in accordance with Guide to The Expression of Uncertainty in Measurement(ISO).