Design oriented simulation of the behavior of PAC consumables and experimental validation of results

Hafnium cathode erosion phenomena are among the most critical issues in the development of plasma arc cutting technology, especially for high current level. In this work, the correlation between the distributions of different quantities inside the chamber of a plasma arc cutting (PAC) torch and the electrode and nozzle erosion has been investigated, by means of a 2-D FLUENT based numerical model. The model has been developed in the design phase of a new Cebora mono-gas plasma torch, in order to address critical issues, experimentally detected. Modelling and numerical simulation have allowed a better understanding of the physical phenomena experimentally observed during the prototype development and have suggested successful design solutions for consumables (in particular nozzle, electrode and primary gas diffusers). Direct correlation was found between modelling results and experimental evidences; numerical simulation has been used to predict electrode and nozzle expected life, proving useful to overcome the critical issues initially pointed out and to significantly improve the expected lifetime of consumables.