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측류유동을 고려한 실린더 주위의 캐비테이션 유동 현상 해석
이병우(B.W. Lee),박원규(W.G. Park),이건철(K.C. Lee) 한국전산유체공학회 2009 한국전산유체공학회 학술대회논문집 Vol.2009 No.4
The cavitating flow simulation is of practical importance for many engineering systems, such as marine propellers, pump impellers, nozzles, injectors, torpedoes, etc. The present work has focused on the simulation of cavitating flow past cylinders with strong side flow. The governing equation is the Navier-Stokes equation based on homogeneous mixture model. The momentum and energy equation is in the mixture phase while the continuity equation is solved liquid and vapor phase, separately. An implicit dual time and preconditioning method are employed for computational analysis. The results from the present solver have been in a fairly good agreement with the experimental data and other numerical results. After the code validation the strong side flow was applied to include the wake flow effect of the submarine.
가로등주 소재 적용 200계 스테인리스강의 용접부 특성
이병우(B. W. Lee),이도경(D. K. Lee),김현수(H. S. Kim),홍성현(S. H. Hong) 한국동력기계공학회 2008 한국동력기계공학회 학술대회 논문집 Vol.2008 No.11
205 stainless steel pipe with street pole material was fabricated by using GTAW process and its welds microstructure and properties were investigated. The welds corrosion behavior of STS 205 pipe in 0.1N sulphuric acid solution and 5% NaCl solution at room temperature was studied using salt spray test and potentiodynamic techniques. The morphology and components of corrosion products on surface of STS 205pipe welds were investigated using SEM/EDX. The tensile strength and yield strength values of STS 205 plate were 600 Mpa and 300 M pa respectively. The welds microstructure of STS 205 pipe showed weld metal, HAZ, substrate regions. The microvickers hardness values STS 205 pipe welds were slightly increased than that of STS 304 pipe welds. The potentiodynamic polarization curve of STS 205 pipe welds exhibited typical active, passive, transpassive behaviour. Corrosion current density(I<Sub>corr</sub>) and critical current density(I<Sub>corr</sub>) values of STS 205 pipe welds in 3.5% NaCl solution were 1.89×10<sup>-6</sup>A/㎠ and 15.8×10<sup>-6</sup>/㎠. Corrosion current ensity(I<Sub>corr</sub>) and critical current density(I<Sub>corr</sub>) values of STS 304 pipe welds in 3.5% NaCl solution were 1.86x10<sup>-6</sup>A/㎠ and 8.89×10<sup>-6</sup>A/㎠. The corrosion resistance of STS 205 pipe welds was similar to its STS 304 pipe welds. 「he red rust on the surface edge of STS 205 pipe welds by salt spray test was formed iron oxide. The STS 205 and 304 pipe welds passive nlms were chromium oxide. Especially, the 205 pipe welds showed good corrosion resistance in 0.1N sulphuric acid. This is attributed to the forming of protective Cr<sub>2</sub>O<sub>3</sub> oxide on the surface of STS 205 pipe welds.
H₂SO₄ 수용액 변화에 따른 철-알루미나이드 합금의 부식특성
이병우(B. W. Lee),최희락(H. R. Choi) 한국동력기계공학회 2005 한국동력기계공학회 학술대회 논문집 Vol.- No.-
Corrosion characterization of Fe-XAl-0.3Y(X=5, 10, 14 wt%) alloys in 0.1~IN sulphuric acid at room temperature was studied using Potentiodynamic techniques. The morphology and components of corrosion products on surface of Fe-aluminide alloys were investigated using SEM/EDX, XRD and EPMA. The potentiodynamic polarization curve of alloys exhibited typical active, passive, transpassive behaviour. Corrosion potential(Ecorr) and corrosion current density(Icorr) values of Fe-XAI-0.3Y alloys followed linear rate law. Ecorr of 10AI alloy and 14AI alloy was ten times lower than 5AI alloy. Icorr of 14AI alloy was five times lower than 5AI alloy. The passive film on the surface of Fe-5AI-0.3Y alloy was formed iron oxide. Fe-10AI-0.3Y and Fe-14AI-0.3Y alloys passive films were aluminium oxide. especially, Fe-14AI-0.3Y alloy showed good corrosion resistance in 0.12~IN sulphuric acid. This is attributed to the forming of protective AI₂O₃ oxide on surface of Fe-14AI-0.3Y alloy.
측류유동을 고려한 실린더 주위의 캐비테이션 유동 현상 해석
이병우(B.W. Lee),박원규(W.G. Park),이건철(K.C. Lee) 한국전산유체공학회 2009 한국전산유체공학회지 Vol.14 No.4
Cavitating flow simulation is of practical importance for many engineering systems, such as marine propellers, pump impellers, nozzles, injectors, torpedoes, etc. The present work has focused on the simulation of cavitating flow past cylinders with strong side flows. The governing equation is the Navier-Stokes equation based on the homogeneous mixture model. The momentum and energy equation is in the mixture phase while the continuity equation is solved liquid and vapor phase, separately. An implicit dual time and preconditioning method are employed for computational analysis. For the code validation, the results from the present solver have been compared with experiments and other numerical results. A fairly good agreement with the experimental data and other numerical results have been obtained. After the code validation, the strong side flow was applied to include the wake flow effects of the submarine or ocean tide.