A numerical analysis in the inert-gas nozzle is performed with a novel injection concept using swirling flow in the laser nozzle, to control the mass transfer near the laser-irradiated area and outlet of the inert gas nozzle. Consequently, the following results were found.
1) By changing swirl strength, it is easy to control the flow pattern as well as the direction of the flow.
2) Swirl number has a critical importance in controlling the flow pattern near the outlet of the tornado nozzle.
3) Negative pressure near the laser-irradiated area can be easily obtained ; accordingly plume is sucked in the inert gas-flow, and thereafter pushed out to the atmosphere together with the gas.
4) Spatter going up towards the laser-mirror in the nozzle, is prevented through the going down inert gas flow, and pushed out to the atmosphere.
Those findings mentioned above are very useful to control the flow pattern to remove the plume and spatters.
