ACOUSTIC DETERMINATION OF TRANSITION TO L AMINAR-FLOW REGIME OF PLASMA TORCH

A plasma torch allows two how regimes: either a laminar (silent mode) or a turbulent mode (noisy mode) which have different properties. The transition of regime is controlled by parameter change (gas how rate, current are and anode diameter) and followed by a noise degree change. This study deals with the characterization of this transition by acou stic methods. Wave and spectral analysis of control information, radia tive energy and acoustic pressure show a frequency peak. The amplitude and frequency of which vary with the running conditions. This frequen tail component of acoustic pressure characterizes accurately the regim e transition.