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레이저가공에서 나타나는 초음속제트의 유동전압 변화에 따른 충돌특성 연구
유동옥(DongOk Yu),이열(Yeol Lee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
Numerical study of the characteristics of micro-sonic/-supersonic jets impinging on a flat plate with a hole was performed, to investigate the role of gas jet to eject melted materials from the cut zone in the laser machining. The variation of the mass flow rate through the hole and the pressure loss of the jet flow were observed for the various total pressure of the jet flow. The present numerical results for the sonic jet impingement show a good agreement with the previous investigators' numerical and experimental results, which proves the accuracy of the present work. Further, for the supersonic nozzle flows, the detailed flow structure and the information of the mass flow rate through the hole were observed for various flow total pressures.
레이저가공에서 나타나는 초음속제트의 사이거리 변화에 따른 충돌특성 연구
유동옥(DongOk Yu),이열(Yeol Lee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
The characteristics of micro-sonic/supersonic jets impinging on a flat plate with a hole was numerically investigated, to observe the role of gas jet in the laser machining. For the various standoff distances between nozzle and plate, the characteristics of the mass flow rate through the hole and the jet flow's pressure loss were observed It was found that the present numerical results for the sonic jet impingement show a good agreement with the previous investigators' study, which reveals the accuracy of the present research. Further, the detailed impinging supersonic flow structures and the information of the mass flow rate through the hole were obtained for the various standoff distances. From this study, it was found that the mass flow rate through the hole was closely related with the total pressure loss caused by the Mach disc on the plate. Finally, a suggestion for the optimal design condition in the laser machining is proposed.
민성규(SeongKyu Min),유동옥(Dongok Yu),이열(Yeol Lee) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.5
Characteristics of micro supersonic jet impinging on a work-piece with a preset hole was experimentally investigated, to observe the role of the assist jet in the laser machining. The observed quantity includes the mass flow rate through the hole in the work-piece, presuming that high mass flux through it results in a high efficiency in the role of assist gas of laser machining. Effects of various parameters, such as nozzle Mach number, flow total pressure, on the mass flow rate through the hole have been observed. Present experimental results for the sonic micro-jet show a good agreement with the numerical/experimental results by previous investigators, and the new results for the supersonic micro-jet reveals that the assist gas issuing from a supersonic nozzle could provide a better efficiency in the laser machining process.