Pulsed laminar arc jet with synchronized suspension injection-spectroscopic studies

• Published in: Journal of physics. Conference series Vol. 550; no. 1; pp. 12020 - 7
• Main Authors: Krowka, J, Rat, V, Chazelas, C, Coudert, J-F
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2014
• Subjects: Devices; Droplets; Electric potential; Emission analysis; Enthalpy; Imaging techniques; Instability; Laminar; Magnetohydrodynamic stability; Optical emission spectroscopy; Physics; Piezoelectricity; Plasma; Plasma jets; Plasma oscillations; Plasma spraying; Stability; Synchronism
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/550/1/012020

The uncontrolled arc plasma instabilities are one of the difficulties encountered in in suspension plasma spraying. The improvement of this process is usually attempted by means of the reduction of arc fluctuations. The following paper presents a new approach to overcome these arc instabilities. The principle is to produce a pulsed laminar plasma jet combined with phased injection of liquid droplets. This is achieved by the particular design of the plasma torch which allows coupling two modes of the plasma oscillations, restrike and Helmholtz. The plasma produced in a new mode is laminar and pulsed, characterized by a modulated enthalpy, what permits to make the synchronization with the suspension injection. The droplets are injected using a piezoelectric device, based on drop-on-demand method, triggered by the voltage signal. The results are evaluated by time-resolved imaging technique and Time- Resolved Optical Emission Spectroscopy.