Acoustic determination of transition to laminar flow regime of plasma torch

A plasma torch allows two flow 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 flow rate, current arc and anode diameter) and followed by a noise degree change. This study deals with the characterization of this transition by acoustic methods. Wave and spectral analysis of control information, radiative energy and acoustic pressure show a frequency peak. The amplitude and frequency of which vary with the running conditions. This frequentative component of acoustic pressure characterizes accurately the regime transition.