Modelling and experimental investigation of microdischarges in zinc metal vapour

This contribution presents complementary modelling and experimental studies of microdischarges in Zn vapour, which are potential sources of gas ignition in flammable atmospheres. The microdischarge in Zn vapour is simulated by a time-dependent one-dimensional unified non-equilibrium model at a constant current of 60 mA and varying the gap lengths to mimic the contact opening in the experiment. The model resolves the spatial structure of the discharge within the gap, enabling us to assess basic plasma parameters, such as electric potential, local temperatures of electrons and heavy particles, number densities of relevant excited states. It further allows us to indicate the main heating processes and the released heat, which is crucial for a thermochemical gas ignition. The model predicts the linear dependence of the voltage on the gap length in agreement with the experiment and identifies the Joule heating as the main heating component. The emission spectrum acquired by optical emission spectroscopy is qualitatively reproduced by the model.