Behaviour of supersonic and subsonic gas jets inside laser cut kerfs

Abstract

A supersonic nozzle tip for high pressure gas assist laser cutting was designed based on the gas dynamic theories and the characteristics of its exit jet at free space were reported in last year’ s conference. More investigations have been carried out since. The effect of stand-off upon the jet momentum was studied using shadowgraphic technique. The behaviour of the gas jet inside the cut slot at different stand-off distance and inlet pressure were investigated. Cutting experiments were carried out using a 3.5 kw CO2 laser.A supersonic nozzle tip for high pressure gas assist laser cutting was designed based on the gas dynamic theories and the characteristics of its exit jet at free space were reported in last year’ s conference. More investigations have been carried out since. The effect of stand-off upon the jet momentum was studied using shadowgraphic technique. The behaviour of the gas jet inside the cut slot at different stand-off distance and inlet pressure were investigated. Cutting experiments were carried out using a 3.5 kw CO2 laser.