Processes in Gerdien arc generated by hybrid gas-water torch

摘要

In the present work the basic principles of the Gerdien arc are described. The arc was generated inthe plasma torch with hybrid stabilisation of the arc by water and argon. The paper discussesphysical processes determining the arc behaviour and governing plasma generation. As the mainmechanism of the plasma generation in the water stabilized part is evaporation from the innersurface of the water vortex, heating and ionisation of vapour, the plasma gas flow rate andcomposition depends on the working parameters of the torch. The amount of the evaporated watercannot be directly measured and was estimated from the mass and power balances of the torch.The flow rate and composition of the generated plasma for different arc currents and argon flowrates have been studied. Increase of the arc current resulted in higher amount of evaporated water,while modification of the argon flow rate did not influence the evaporation rate.