Experimental studies were undertaken to investigate the shielding gas characteristics of various welding nozzle designs. Qualitative (smoke visualization and PLIF) and quantitative (PIV) imaging and analysis of existing welding nozzle designs were performed in order to determine the important parameters that affect the shielding gas behaviour in the nozzle passages, as well as in the flow immediately upon exiting the nozzle, under both cold flow and live welding conditions. It was found that nozzle geometry, shielding gas flow rate, contact tip position and internal gas diffuser configuration were important in the optimization of welding nozzle design. The results obtained from these parametric studies were used in developing new nozzle designs with improved shielding gas flow characteristics.

This research was conducted in collaboration with Tregaskiss Ltd. through the NRC-IRAP Program.