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수치기법을 이용한 저소음 얼터네이터 냉각팬의 DFSS 최적 설계
김욱(W. Kim),전완호(W.-H. Jeon),현재진(J.-J. Hyun),임철구(C.-K. Lim),이성하(S.-H. Lee) 한국전산유체공학회 2008 한국전산유체공학회 학술대회논문집 Vol.2008 No.-
An alternator which converts mechanical rotating energy into electric energy is an important component of a vehicle. It operates in broad range from 3000 RPM to 18000 RPM. So, sufficient flow rate and low noise are needed in such broad operating range for a cooling fan of this alternator. In current study, the cooling fan of an alternator is developed through DFSS process and numerical analysis. In order to calculate flow rate and noise level, SC/Tetra and Flow Noise are used respectively, for a new developed fan, compared with original model, numerical result shows 3 dBA reduction and measured value shows 4 dBA reduction.
수치해석기법을 이용한 노트북 소형 냉각팬의 유동 및 소음 특성에 관한 연구
전완호(W.H. Jeon),임태균(T.G. Lim),御法川?(Gaku Minorikawa),宮原雅晴(Masaharu Miyahara) 한국전산유체공학회 2013 한국전산유체공학회 학술대회논문집 Vol.2013 No.10
In recent years, the size of a notebook gets thinner and smaller. Its inner size makes problems in cooling fan performance, system installation condition, and so on. In this study, a small turbofan was installed in the very narrow gap like a notebook system, in order to generate similar condition to a real product. Experiments were performed to measure the fans performance and the flow and noise characteristics, results were compared with computational ones. CFD simulation predicted P-Q curve under about 5% error in high flowrate and its trend agreed with experiment data over the flow range. The noise was measured at a distance of 100 mm from a rotation axis direction of an impeller. The measured data corresponded well with computational ones of broadband and BPF noise analyzed by a commercial program(FlowNoise).
전완호(W.H. Jeon),박창환(C.H. Park) 한국전산유체공학회 2017 한국전산유체공학회지 Vol.22 No.2
The Present work describes the prediction method for the unsteady flow field and the aeroacoustic noise of an axial fan which has 3 blades with high sweep angle. Unsteady Reynolds-averaged Navier-Stokes(URANS) and large eddy simulation(LES) numerical approaches were adopted for prediction of unsteady flow field around the axial fan. Ffowcs-Williams and Hawkings equation with dipole assumption was used to calculate the aeroacoustic sound generated from the axial fan. Although both URANS and LES offer good estimates of the overall sound spectrum including blade pass frequency, LES produces more accurate and reliable results especially for the prediction of broadband and tonal noise at high frequency range. Through fast Fourier transform(FFT) analysis of noise source strength, the noise source of tonal peak at 750Hz is identified as the vortex separation at 1/4 position of the blade tip. It is also found that the noise source of broadband peak between 1200Hz and 1400Hz is located from center of tip to trailing edge.
범용 유동해석 데이터 형식을 이용한 유동소음 수치해석 프로그램 개발
최익황(I. H. Choi),김연호(Y. H. Kim),김준희(J. H. Kim),임태균(T. G. Lim),전완호(W. H. Jeon) 대한기계학회 2017 대한기계학회 춘추학술대회 Vol.2017 No.11
Recently, the noise problem has been recognized as a serious problem in addition to pollution such as fine dust due to industrialization. In this paper numerical analysis methods using computational fluid dynamics (CFD) and computational aeroacoustics (CAA) was performed using the CFD general notation system (CGNS) and developed the S/W for visualizing the analyzed result of flow noise. The aerodynamic noise analysis S / W has been developed to deal larger models and larger grids.
회전톱 재단기의 미세먼지 집진효율 향상을 위한 형상 설계 개선
김기희(G.H Kim),이희남(H.N Rhee),전완호(W.H Jeon) 한국전산유체공학회 2011 한국전산유체공학회 학술대회논문집 Vol.2011 No.5
Dust released from the rotating timber cutting process causes various kinds of diseases as well as safety issues. Although there were lots of efforts to reduce the amount of dust by installing large-sized dust collectors or by using expensive high-quality cutters, they proved to be not so effective. In this study we want to modify and improve the design of the rotary cutter system to prevent dust from being released to the environment as possible by using computational fluid dynamics (CFD) analysis. We have developed CFD models of the conventional cutter and several design modifications. Through the CFD analysis the characteristics of the air flow was predicted, and then the behavior of dust produced during the cutting process was analyzed for different designs. The most efficient design feature to capture dust inside the cutter as much as possible was chosen based on the CFD analysis results. Finally the prototype of the ratary saw machine was constructed and tested to check the dust capturing efficiency, which result is reasonably consistent with the predicted performance through the CFD analysis.
전완호(W. H. Jeon),임태균(T. G. Lim),御法川 ?(Gaku Minorkkawa),宮原 雅晴(Masaharu Miyahara) 한국소음진동공학회 2013 한국소음진동공학회 학술대회논문집 Vol.2013 No.10
In recent years, a notebook like an ultrabook gets thinner. Its thickness causes problems in cooling fan performance, system installation condition, and so on. In this study, we installed a small turbofan in notebook system with very narrow gap in order to generate similar condition to a real product. Experiments were performed to measure the fan`s performance and the flow and noise characteristics, its results were compared with computational ones. Prediction of P-Q curve using CFD showed under about 5% error in high flow rate and its trend was agreed with experimental one over the flow field. Experimental data to measure the noise at a distance of 100 mm from a rotation axis direction of an impeller corresponded well with computational ones of broadband and BPF noise. The noise experiments to measure at a distance of 100 mm from a rotation axis direction of an impeller corresponded well with computational ones of broadband and BPF noise. Especially, tip part of impeller blade and part of exit and bottom near cut off of a casing were dominant noise source in an analysis by a commercial program(FlowNoise)