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KSTAR(Korea Superconducting Tokamak Advanced Research) 냉각 시스템에 대한 열해석 연구
김홍원(H. W. Kim),하지수(J. S. Ha),김대순(D. S. Kim),이종석(J. S. Lee),최창호(C. H. Choi) 대한기계학회 2003 대한기계학회 춘추학술대회 Vol.2003 No.11
A study on the engineering design and numerical thermo-hydraulic analysis for KSTAR TF coil structure<br/> cooling system has been conducted. The numerical analyses have been done to verify the engineering design<br/> of cooling using the commercial code, FLUENT and in-house code for calculating helium properties which<br/> varies with cooling tube’s heat transfer. Through the engineering design process based on the steady heat<br/> balance concepts, the circular stainless steel tube with inner diameter of 4 mm for TF coil has been selected as<br/> cooling tube. From normal operation mode analysis results, total 28 cooling tubes were finally chosen. Also,<br/> three dimensional cool down analysis for TF coil with designed cooling tube was satisfied with next three<br/> design criteria. First is cooling work termination within a month, second is maximum temperature difference<br/> within 50 K in TF coil structure and third is exit helium pressure above 2 bar. Consequently, these cool down<br/> scenario results can afford to adopt as operating scenario data when KSTAR facilities operate.
크랭크샤프트 국부화염가열시 예비성형체 길이가 축방향 온도분포에 미치는 영향
송민철(M. C. Song),김대순(D. S. Kim) 한국소성가공학회 2011 한국소성가공학회 학술대회 논문집 Vol.2011 No.5
The crankshaft for 4-stroke marine diesel engine is produced by TR forging providing a continuous grain flow. The preform of crankshaft is a round bar with a ring groove. Partial flame heating and forging are performed sequentially in TR forging process for a large crankshaft. The axial length of the preform is shortened as TR forging is progressing. In this study, the effect of axial length change of the preform on the axial temperature distribution in the heated part was investigated during TR forging process. Theoretical approach with the assumption of the preform having a cooling fin was performed to obtain the steady state temperature distribution of the preform along the axial direction. The validity of theoretical approach was verified by comparing heat transfer analysis results with FEM analysis results. Based on this study, it was found that the effect of axial length change of preform on the axial temperature distribution in the heated part would be negligible in case of constant temperature inside furnace.
송민철(M. C. Song),김대순(D. S. Kim) 한국소성가공학회 2012 한국소성가공학회 학술대회 논문집 Vol.2012 No.5
The purpose of this study is to design the proper preform for TR forging, a closed-die forging process in order to secure the dimensional accuracy of the forged crank throw under the same material volume, die and forging load. Considering the kinematic characteristics of TR device and the target forged shape of crank throw, the analytical design of preform could have a various choice of geometry variables such as the pin diameter of preform, volumeallo cation and angle between pin and web of preform. The effect of the geometry variables on the dimensions of the crank throw was evaluated by using FEA in order to determine the geometry detail of the preform. According to FEA results, it can be concluded that the pin of the preform should be controlled as same as volume of the pin of the final product. The web diameter of preform should be also maximized as far as the web length of the preform should be controlled smaller than the web thickness of the target forged crank throw.