Knowledge of transport phenomena and keyhole evolution is important for controlling laser welding process. However, it is still not well understood by far due to the complex phenomena occurring in a wide temperature r...Knowledge of transport phenomena and keyhole evolution is important for controlling laser welding process. However, it is still not well understood by far due to the complex phenomena occurring in a wide temperature range. A transient 3D model including heat transfer, fluid flow and tracking of free surface is built in this study. The transport phenomena are investigated by calculating the temperature and velocity fields. The 3D dynamic keyhole evolution process is revealed through tracking free surface using volume-of-fluid method. The results show that the keyhole deepening speed decreases with laser welding process before the quasi-steady state is reached. The plasma can greatly affect the keyhole depth through absorbing a great amount of laser energy and thus lowering the recoil pressure. Moreover, the relationship between keyhole depth and weld penetration is also discussed. This paper can help to better understand the dynamics in molten pool and then improve laser welding process.展开更多
Google Earth(GE)作为一款流行的三维虚拟地球软件,可以方便直观地显示电网地理信息系统(GIS)信息。针对基于GE进行电力系统GIS建设的问题,阐述了GE这款软件的特点,详细介绍了它应用于电力GIS的优势。基于GE支持的数据格式为KML的情况,...Google Earth(GE)作为一款流行的三维虚拟地球软件,可以方便直观地显示电网地理信息系统(GIS)信息。针对基于GE进行电力系统GIS建设的问题,阐述了GE这款软件的特点,详细介绍了它应用于电力GIS的优势。基于GE支持的数据格式为KML的情况,把电力系统GIS相关数据转化为KML格式。研究结果表明:基于GE能够实现电网地理信息、电网调度信息,以及电网规划信息的可视化显示。展开更多
基金Projects(51804348,51804196) supported by the National Natural Science Foundation of China
文摘Knowledge of transport phenomena and keyhole evolution is important for controlling laser welding process. However, it is still not well understood by far due to the complex phenomena occurring in a wide temperature range. A transient 3D model including heat transfer, fluid flow and tracking of free surface is built in this study. The transport phenomena are investigated by calculating the temperature and velocity fields. The 3D dynamic keyhole evolution process is revealed through tracking free surface using volume-of-fluid method. The results show that the keyhole deepening speed decreases with laser welding process before the quasi-steady state is reached. The plasma can greatly affect the keyhole depth through absorbing a great amount of laser energy and thus lowering the recoil pressure. Moreover, the relationship between keyhole depth and weld penetration is also discussed. This paper can help to better understand the dynamics in molten pool and then improve laser welding process.
