http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
수치해석을 이용한 친환경 자동차용 전력변환장치의 유로 변화에 따른 냉각 성능 예측에 관한 연구
노정훈(J.H. Noh),이현경(H.K. Lee),고동신(D.S. Ko),허덕재(D.J. Hur) 한국전산유체공학회 2018 한국전산유체공학회지 Vol.23 No.4
In this study, the cooling performance of various cooling water channels was evaluated by numerical analysis in order to reduce the weight reduction, miniaturization and high efficiency of the power converter (DC-DC converter) mounted on the electric vehicle. As the analysis environment, heat sources (Diode, Rectifier, Inductors) have the constant heat generation values and fixed position. The pressure drop, internal maximum temperature and calorific value recovered by the cooling water were predicted according to the change of volume flow rate and cooling water flow direction. From the results, it was confirmed that the performance were changed according to the cooling channel pattern at the same volume flow rate, and the amount of volume flow rate at each pattern. In addition, it was found that the direction of the cooling water is an important factor for determining the cooling performance, and the optimum design of heat source layout is required for improving the cooling performance. The results obtained from this study would provide an important guideline for designing the cooling instrument as well as power conversion system, and would be helpful in selecting the dominant factors for the optimum design.
후방 캔 압출 공정에서 표면 변형 형태에 대한 펀치 형상의 영향
노정훈(J. H. Noh),김동현(D. H. Kim),황병복(B. B. Hwang) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.10
This paper is concerned with the analysis on the surface stress profiles of AISI 1015 steel in backward extrusion process. Heavy surface stress such as surface expansion appeared in backward can extrusion process usually leads to very severe tribological conditions along the interface between workpiece and punch land. In the present study, influence on the punch face angle and reduction has been investigated in terms of the surface stress profiles such as surface expansion, pressure exerted on the tool surface between tool and workpiece, respectively. The main goal of this study is to examine the influence of process conditions such as degree of reduction in area and geometries of punch face on the deformation pattern of the model material in backward extrusion, especially for surface stresses. It is well known that among various surface stresses, surface expansion and contact pressure distribution along the die-workpiece interface are closely related to the condition of lubrication at the interface for both solid and liquid lubricants, and contact pressure and sliding distance between workpiece and tool are essential parameters to evaluate the tool wear. The geometrical parameters employed in analysis include the punch face angle of the punch nose as well as reduction ratio. Extensive simulation has been conducted by applying rigid-plastic finite element method to backward can extrusion process under various geometrical conditions. The simulation results are summarized in terms of surface stresses such as surface expansion, pressure and comparison of surface loads for different process conditions, which constitute of surface stress profiles. It was found from the present study that the surface expansion is more influenced by reductions than the punch nose angle.