Analysis of a Pulsed Detonation Thermal Spray Applicator

Abstract

Pulsed detonation thermal spray applicators are used to deposit particulate-based coatings on metal components. The coatings usually consist of a unique class of thermal spray materials that are widely employed in numerous industries to enhance the surface of metal components. This paper presents an analysis and numerical simulation of an open tube pulsed detonation thermal spray applicator. Calculations are made to determine the theoretical detonation states attainable for typical operating conditions and to track the particle trajectories as they traverse the barrel, eventually impacting the target workpiece. The present investigation focuses on the combustion of acetylene in oxygen, diluted with nitrogen. Key parameters studied are: nitrogen dilution percentage, oxygen-carbon ratio, barrel location of solid-particle axial injection, and size of the injected particles. Results are presented on the effect of these design parameters on several important quantities including: detonation speed, velocity of the detonation product gases, detonation pressure, detonation temperature, temperature and velocity profiles of the solid particle as it travels through the pulsed detonation thermal spray applicator, percentage melt history of the solid particles, and temperature, velocity, and percentage melt of the solid as it impacts the workpiece.