Numerical study on the behavior of titanium particles in the process of warm spraying

• Published in: Welding in the world 2022, Vol.66 (7), p.1305-1314
• Main Authors: Han, Xing, Li, Chang, Gao, Xing, Chen, Xinxue, Liu, Zhaotai
• Format: Article
• Language: English
• Subjects: Alloy powders; Chemical reactions; Chemistry and Materials Science; Combustion chambers; Combustion products; Computational fluid dynamics; Divergence; Flame temperature; Flow characteristics; Fluid flow; K-epsilon turbulence model; Mass flow rate; Materials Science; Mathematical models; Metallic Materials; Particle size; Powder spraying; Research Paper; Solid Mechanics; Static pressure; Theoretical and Applied Mechanics; Titanium alloys; Titanium base alloys; Turbulence models; Vapor phases
• ISSN: 0043-2288; 1878-6669
• DOI: 10.1007/s40194-022-01292-7

The flame flow characteristics, combustion mechanism, and particle flight behavior of warm spraying have been studied to broaden the warm spraying application of phase-sensitive materials. We used computational fluid dynamics (CFD) to study the flight behavior of titanium alloy powder particles during warm spraying. The renormalization group (RNG) and the k-ε turbulence model were used to solve the gas phase model. The single-step chemical reaction model and the eddy dissipation model (EDM) were combined to simulate the spray combustion reaction. On this basis, the discrete phase (DPM) model of titanium particles in the flame was carried out by the Lagrangian method to determine the particle flight behavior. In the study, the static pressure and flame temperature of the combustion products in the combustion chamber reached 0.39 MPa and 3305 K, respectively. The flame flows through the Laval nozzle with the convergence and divergence by 1668 m/s. It is an effective way to control the particle temperature without undesirable changes in particle velocity by adjusting the mass flow rate of the cooling gas. Warm spraying is more suitable for phase-sensitive and complex spraying materials. The flight behavior of small particles will be easily affected by the flame flow, while the large particles maintain their momentum and energy. The particle diameter and injection velocity were limited to no more than 55 μm and 20 m/s, which can effectively prevent particles from adhering and blocking the inner wall of the barrel.