J. M. Badie
C. N. R. S., Institut de Science et de Genie des Materiaux et Procedes B. P. 5, Odeillo, F-66125 Font-Romeu Cedex
J. Bresson
L.M.A.I. UNIV. PERPIGNAN, 52 av. de Villeneuve, 66860 Perpignan cedex
A. Daif
I.M.P.-CNRS, BP.5, Odeillo, 66125 Font-Romeu cedex - France
B. Granier
Institut de science et de Genie des Materiaux et Procedes B.P.5 Odeillo 66125 Font - Romeu, France
Voltage, current, acoustic pressure and light fluctuations from a plasma torch were
recorded and analysed by fast Fourier transform (FFT). These measurements were
performed for three nozzle diameters, and varying the argon plasma gas flow rate up to 30
l/min. At high flow rates the results confirm the observations depicted in the litterature
concerning the good correlation between these different signals. At low gas flow rate a
peak in the acoustic pressure spectra which maximum intensity coincide with the laminar-turbulent
transition could be used to characterize this transition.