A Particle-Tracking-Velocimetry (PTV) Investigation of Liquid Injection in a DC Plasma Jet

• Published in: Journal of thermal spray technology Vol. 23; no. 3; pp. 340 - 353
• Main Authors: Damiani, David, Tarlet, Dominique, Meillot, Erick
• Format: Journal Article
• Language: English
• Published: Boston Springer US 01.02.2014; Springer
• Subjects: Analytical Chemistry; Applied sciences; Characterization and Evaluation of Materials; Chemistry and Materials Science; Corrosion and Coatings; Exact sciences and technology; Machines; Manufacturing; Materials Science; Metals. Metallurgy; Peer Reviewed; Processes; Production techniques; Surface treatment; Surfaces and Interfaces; Thin Films; Tribology; liquid injection; optical diagnostics; nanomaterials; plasma spraying; particle-tracking-velocimetry (PTV); Plasma; Plasma jet; Hot spraying; Plasma spraying; Surface treatment
• ISSN: 1059-9630; 1544-1016
• DOI: 10.1007/s11666-013-0050-5

The present article describes experimental results of liquid injection in a thermal plasma jet by particle-tracking velocimetry (PTV). This technique delivers an in-situ real-time analysis of the liquid breakup and measures the velocities and the trajectories of the particles. The observations were done within the 10 mm surrounding the injection location where the plasma brightness is considerable. First, a validation of the proposed investigation method was carried out in a slower plasma jet. Subsequently, PTV measurements within faster plasma jets, resulting in a set of trajectories, were compared with trajectories achieved through optical diagnostics based on a simple shadow-graph technique proposed by Damiani et al. [Injection d’un liquide au sein d’un jet plasma thermique: optimisation de la trajectoire des particules, Proceedings of Congrès Francophone de Techniques Laser, CFTL 2010, Vandoeuvre lès nancy, France, 2010 (in French)]. These trajectories indicated that a higher plasma flow rate was required to spray all droplet sizes in the axis of the flow, thereby enabling an optimal spraying (then coating) application for producing nanostructured thin layers. This study showed that the liquid injection parameters are of main importance to obtain optimal injection and plasma parameters to achieve the required coating properties.