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CFD에 의한 2차원 후향계단에서의 재부착 유동특성에 관한 연구
최영도(Y. D. Choi),이영호(Y. H. Lee) 한국전산유체공학회 1998 한국전산유체공학회 학술대회논문집 Vol.1998 No.-
The present study is aimed to investigate flow characteristics of Two dimensional backward-facing step by numerical approach. A convection conservative difference scheme based upon SOLA algorithm is used for the solution of the two-dimensional incompressible Navier-Stokes equations to simulate the laminar, transitional and turbulent flow conditions at which the experimental data can be available for the backward-facing step. The twenty kinds of Reynolds number are used for the calculations. In an effort to demonstrate that the reported solutions are dependent on the mesh refinement, computations are performed on seven different meshes of uniformly increasing refinement. Also to investigate the result of inflow dependence, two kinds of the inflow profile are chosen for the laminar flow. As criterion of benchmarking the result of numerical simulation, reattachment length is used for the selected Reynolds numbers.
이승엽(S. Y. Lee),최민선(M. S. Choi),최영도(Y. D. Choi),이영호(Y. H. Lee) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-
The mixers are used in various industrial fields where it is necessary to mix two reactants in a short period of time. However, despite their widespread use, complex unsteady flow characteristics of industrial mixers has not been investigated systematically. This paper presents calculated results of the unsteady flow characteristics in a Industrial Mixer by CFD analysis. In this research, axial type impellers are used. The rotating speed of impellers is 1800 rpm. The results show that quite different flow patren if found between steady and unsteady calculation.
횡류수차의 러너 블레이드 개수변화에 따른 속도와 압력 분포
임재익(J. I. Lim),최영도(Y. D. Choi),김유택(Y. T. Kim),이영호(Y. H Lee) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Many countries are interested in CO₂ -It is greenhouse gas which causes global warming. -output reduction. Therefore, Many Researchers are interested in renewable energy development. Small hydro power is clean and renewable energy that does not discharge CO₂. Relatively high manufacturing cost by the complex structure of the turbine is the highest barrier for developing the small hydropower turbine. Therefore, a cross-flow turbine is adopted because of its simple structure and high possibility of applying to small hydropower. In this study, made experiment result in research that utilize Zhao relationship hydro turbine model about cross-flow turbine comparison target. The purpose of this study is the variation of the number of runner blade to improve the performance. Optimization of the turbine structure has been made by the analysis of the turbine performance with the variation of the number of runner blade using a commercial CFD code. The results show that the number of runner blade give considerable effect on the performance of the turbine.
전현태(H. T. Jeon),남상현(S. H. Nam),최영도(Y. D. Choi),김유택(Y. T. Kim),이영호(Y. H. Lee) 한국동력기계공학회 2007 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Small hydropower attracts attention because of its clean, renewable and abundant energy resources to develop. However, suitable draft-tube type is not determined yet because of its complicated internal flow and unstable turbine performance at the partial flow rate by the influence of the draft tube configuration. Therefore, it is necessary to study the influence of draft tube shape. The purpose of this study is to investigate the influence of the draft tube shape to its internal flow using CFD analysis. The results using two different computational models (draft tube without runner and draft tube with runner) are compared. The result which is computed without runner show that large secondary flow occurs at the curve area of the draft tube and the secondary flow goes out to the outlet of the draft tube. Another result which is computed with runner show that internal flow has complex flow in the whole flow field of the draft tube.
이진우(J. W. Lee),윤치호(C. H. Yoon),박종명(J. M. Park),최영도(Y. D. Choi),이영호 (Y. H. Lee) 한국동력기계공학회 2009 한국동력기계공학회 학술대회 논문집 Vol.2009 No.11
The development of lifting pumps that lift minerals to a mining vessel are one of the vital parts of the commercial mining process. Lifting pumps with a high total head are needed as lifting pumps transfer minerals from the deep sea to a waiting vessel. Accordingly, when we designed the lifting pumps we needed to design the centrifugal pump with a high total head. However, that kind of pump has a small specific speed and it created a small passageway, so they had a problem transferring the minerals. Therefore, we designed a mixed flow pump which has a wider passage way for minerals to flow. Technology to design the pump requires a lot of experience, so more research into how the pump operates is necessary. In this research, I examined the internal flow of the pump by CFD to gather basic information for developing the pump's performance.