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적응형 인자 모델을 이용한 개선된 진공펌프 상태진단에 관한 연구
이규호,이수갑,임종연,정완섭,Lee, Kyu-Ho,Lee, Soo-Gab,Lim, Jong-Yeon,Cheung, Wan-Sup 한국진공학회 2011 Applied Science and Convergence Technology Vol.20 No.3
본 논문에서는 건식 진공펌프에서 측정한 다중 변수로 구성된 배치데이터의 통계적인 특성을 소개한다. 흡입구 및 배출구 압력과 부스터/드라이 펌프의 소비전류와 같은 상태변수의 변위분포는 2개나 3개의 특정적인 구간으로 나뉘는 특성이 있다. 이런 관측을 통해 발견한 통계학적 특성을 나타내기 위해 적응형 인자 모델(APM)을 사용하였다. APM 모델기반의 배치 데이터는 건식 진공펌프의 상태를 진단하는데 적절함을 증명하였고, 이전의 동적 시간 왜곡 알고리즘과 비교하였을 때 계산시간 및 필요 메모리 면에서 효율적임을 확인하였다. This paper introduces statistical features observed from measured batch data from the multiple operation state variables of dry vacuum pumps running in the semiconductor processes. The amplitude distribution characteristics of such state variables as inlet pressures, supply currents of the booster and dry pumps, and exhaust pressures are shown to be divided into two or three distinctive regions. This observation gives an idea of using an adaptive parametric model (APM) chosen to describe their statistical features. This modelling, in comparison to the traditional dynamic time wrapping algorithm, is shown to provide superior performance in computation time and memory resources required in the preprocessing stage of sampled batch data for the diagnosis of running dry vacuum pumps. APM model-based batch data are demonstrated to be very appropriate for monitoring and diagnosing the running conditions of dry vacuum pumps.
풍력 발전기 소음의 진폭변조가 소음 인지와 불쾌감에 미치는 영향
이승훈(Lee, Seung-Hoon),김규태(Kim, Kyu-Tae),이수갑(Lee, Soo-Gab) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.11
Wind turbines produce aerodynamic noise which fluctuate periodically at a blade passing frequency. This sound characteristic is called amplitude modulation, or swishing sound. Several previous studies claimed that this amplitude modulation has a possibility to increase noise annoyance. Thus, this study performed a listening test to find the relationship between the amplitude modulation in wind turbine noise on noise annoyance. The stimuli for the listening test was recorded from a 1.5MW wind turbine in Jeju island. The result of the listening test shows that the amplitude modulation in wind turbine noise significantly increase noise annoyance. Moreover, this study analytically examined the effect of amplitude modulation on noise perception. The result indicates that amplitude modulated sound can be easily perceived even though the background noise level is higher than the sound level of the signal.
고속 회전 풍력 시스템의 로터 설계 인자에 따른 공력 소음 해석 연구
이승민(Lee, Seung-Min),김호건(Kim, Ho-Geon),손은국(Son, Eun-Kuk),이수갑(Lee, Soo-Gab) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.06
This study describes aerodynamic noise of high speed wind turbine system, which is invented as a new concept in order to reduce the torque of main shaft, for design parameters of the rotor blade. For parametric study of high speed rotor aerodynamic noise, Unsteady Vortex Lattice Method with Nonlinear Vortex Correction Method is used for analysis of wind turbine blade aerodynamic and Farassat1A and Semi-Empirical are used for low frequency noise and airfoil self noise. Parameters are chord length, twist and rotational speed for this parametric research. In the low frequency range, the change of noise is predicted the same level as each parameters varies. However, in case of broadband noise of blade, the change of rotational speed makes more variation of noise than other parameters. When the geometric angles of attack are fixed, as the rotational speed is increased by 5RPM, the noise level is increased by 4dB.
신동신,임종수,김창성,노오현,이수갑,Shin, Dong-Shin,Im, Jong-Soo,Kim, Chang-Seong,Rho, O-Hyun,Lee, Soo-Gab 한국유체기계학회 1999 한국유체기계학회 논문집 Vol.2 No.1
Flow field and near-field noise of a centrifugal fan has been studied with an efficient compressible method and STAR-CD. The flow field of the centrifugal fan is assumed to be two-dimensional. Most of the compressible studies have been done by inviscid solver because viscous simulation shows little difference. The near field noise is estimated in terms of sound pressure level in frequency domain transformed from the computed pressure fluctuations using FFT. The simulation has been done on various design elements such as impeller blade shapes, the number of blades and cut-off clearance. The comparison shows that the number of blades has a significant effect on near-field noise without losing aerodynamic performance.
난류-캐스케이드 상호 작용에 의한 광대역 소음장의 시간영역 계산
정성수(Jung, Sung-Soo),정완섭(Cheung, Wan-Sup),이수갑(Lee, Soo-Gab),정철웅(Cheong, Cheol-Ung) 한국소음진동공학회 2006 한국소음진동공학회 논문집 Vol.16 No.3
The objective of the present work is to develop a time-domain numerical method of broadband noise in a cascade of airfoils. This paper focuses on dipolar broadband noise sources, resulting from the interaction of turbulent inflows with the flat-plate airfoil cascade. The turbulence response of a two-dimensional cascade is studied by solving both of the linearised and the full nonlinear Euler equations employing accurate higher order spatial differencing, time stepping techniques and non-reflecting inflow/outflow boundary condition. The time-domain result using the linearised Euler equations shows good agreement with the analytical solution using the modified LINSUB code. Through the comparison of the nonlinear time-domain result using the full nonlinear Euler equations with the linear, it is found that the acoustic mode amplitude of the nonlinear response is less than that of the linear response due to the energy cascade from low frequency components to the high frequency ones. Considering the merits of the time-domain methods over the typical time-linearised frequency-domain analysis, the current method is expected to be promising tools for analyzing the effects of the airfoil shapes, non-uniform background flow, linear-nonliear regimes on the broadband noise due to turbulence-cascade interaction.
Design of Low Noise Airfoil for Use on Small Wind Turbines
김태형(Kim, Tae-Hyung),이승민(Lee, Seung-Min),김호건(Kim, Ho-Geon),이수갑(Lee, Soo-Gab) 한국신재생에너지학회 2009 한국신재생에너지학회 학술대회논문집 Vol.2009 No.11
Wind power is one of the most reliable renewable energy sources and the installed wind turbine capacities are increasing radically every year. Although wind power has been favored by the public in general, the problem with the impact of wind turbine noise on people living in the vicinity of the turbines has been increased. Low noise wind turbine design is becoming more important as noise is spreading more adverse effect of wind turbine to public. This paper demonstrates the design of 10 kW class wind turbines, each of three blades, a rotor diameter 6.4m, a rated rotating speed 200 rpm and a rated wind speed 10 m/s. The optimized airfoil is dedicated for the 75% spanwise position because the dominant source of a wind turbine blade has been known as trailing edge noise from the outer 25% of the blade. Numerical computations are performed for incompressible flow and for Mach number at 0.145 and for Reynolds numbers at 1.02{times}10<sup>6</sup> with a lift performance, which is resistant to surface contamination and turbulence intensity. The objective in the low design process is to reduce noise emission, while sustaining high aerodynamic efficiency. Dominant broadband noise sources are predicted by semi-empirical formulas composed of the groundwork by Brooks et al. and Lowson associated with typical wind turbine operation conditions. During the airfoil redesign process, the aerodynamic performance is analyzed to minimize the wind turbine power loss. The results obtained from the design process show that the design method is capable of designing airfoils with reduced noise using a commercial 10 kW class wind turbine blade airfoil as a basis. The new optimized airfoil clearly indicates reduction of total SPL about 3 dB and higher aerodynamic performance.
김선우(Kim, Sun-Woo),장길수(Jang, Gil-Soo),이수갑(Lee, Soo-Gab),송민정(Song, Min-Jeong),장세명(Chang, Se-Myong),전지현(Jeon, Ji-Hyun),안병옥(Ahn, Byung-Og) 한국소음진동공학회 2002 한국소음진동공학회 논문집 Vol.12 No.6
Rating scales for environmental noise are varied in their calculation procedure. Among them WECPNL (weighted equivalent continuous perceived noise level) is the rating scale for aircraft noise currently being used in domestic and applied only for aircraft noise. However $L_{dn}$ calculated from $L_{eq}$ $L_{eq}$ is used as a rating scale for not only aircraft noise but also environmental noise. Besides, it is easy to calculate and internationally preferred. It is, therefore, not adequate for the evaluation of residents' exposure. Moreover it is very difficult to measure the aircraft noise by WECPNL due to the complicated calculating procedures if automatic measuring system is not used. Accordingly. this study aims to propose alternative evaluation procedure for the aircraft noise. To achieve this purpose, the data measured by automatic measuring system were gathered and calculated with three evaluation procedures : WECPNL $L_{eq}$ and $L_{dn}$, and the results calculated from different methods were compared and analyzed.
비선형 구속 와류 보정법을 이용한 수평축 풍력 발전기의 공력 해석
김호건(Kim, Ho-Geon),이승민(Lee, Seung-Min),이수갑(Lee, Soo-Gab) 한국신재생에너지학회 2008 한국신재생에너지학회 학술대회논문집 Vol.2008 No.05
Nonlinear Vortex Strength Correction Method is developed for improvement of vortex lattice method which can't calculate the separated flow conditions and the viscous effect. In this method, the vortex strength on the blade surface is determined by matching the lift force from vortex lattice method with the lift force from aerodynamic coefficients table as the same circulation is added to or subtracted from all chord wise vortices. For considering the nonlinearities due to the neighboring blade sections, sophisticated Newton-Rapson algorithm is applied. The validation of this method was done by comparing the simulations with the measurements on the NREL Phase-VI horizontal axis wind turbine(HAWT) in the NASA Ames wind tunnel under uniform conditions. This method gives good agreements with experiments in most cases.
혼합 영역 RANS-LES를 이용한 톱니 뒷전 유동 및 소음장의 계산
김태형(Kim, Tae-Hyung),이승훈(Lee, Seung-Hoon),이수갑(Lee, Soo-Gab) 한국소음진동공학회 2012 한국소음진동공학회 논문집 Vol.22 No.5
The evaluation of a zonal RANS-LES approach is documented for the prediction of broadband noise generated by the flow past unmodified and serrated airfoil trailing edges at a high Reynolds number. A multi-domain decomposition is considered, where the acoustic sources are resolved with a LES sub-domain embedded in the RANS domain. A stochastic vortex method is used to generate synthetic turbulent perturbations at the RANS-LES interface. The simulations are performed with a general-purpose unstructured control-volume code FLUENT. The far-field noise is calculated using the aeroacoustic analogy of Ffowcs Williams-Hawkings. The results of the simulation are validated through the full-scaled wind turbine acoustic measurements. It is found that the present approach is adequate for predicting noise radiation of serrated trailing edge flow for low noise rotor system.