MODELLING OF SUPERSONIC GAS FLOW OFNOZZLES FOR LASER CUTTING SYSTEMS

摘要

Nozzles for laser cutting systems play an important role for material processing. Thernunderstanding and enhancement of supersonic gas flow of nozzles makes it possible tornproduce high-quality surfaces without any brow through an efficient drive out of materialrnwith less cutting gas consumption.rnDifferent nozzle designs have been studied with various experimental and numerical methods.rnThe gas density gradient was observed by the “Schlieren”-technique and the velocityrndistribution was measured with laser doppler anemometer. The supersonic gas flow of nozzlesrnfor laser cutting systems has been modelled with CFD simulations. The comparison of thesernmethods has shown that CFD simulations in conjunction with ‘Schlieren’ technique arernsuitable and efficient tools for designing high performance nozzles for laser cutting systems.rnReal life cutting experiments were performed with a selection of promising nozzle designsrnand have been analyzed concerning the cutting quality and gas consumption. The influence ofrnthe laser parameters such as focal position and cutting speed has been included in thesernexperiments.As consequence a new nozzle has been designed requiring 25% less cutting gas whilernsimultaneously increasing the cutting speed 30% and maintaining the cutting qualityrncompared to our standard product.