Computational fluid dynamics analysis of a wire-feed, high-velocity oxygen fuel (HVOF) thermal spray torch

• Published in: Journal of thermal spray technology Vol. 7; no. 3; pp. 374 - 382
• Main Authors: LOPEZ, A. R, HASSAN, B, OBERKAMPF, W. L, NEISER, R. A, ROEMER, T. J
• Format: Journal Article
• Language: English
• Published: Heidelberg Springer 01.09.1998; Springer Nature B.V
• Subjects: Applied sciences; Combustion; Combustion products; Computational fluid dynamics; Curved; Exact sciences and technology; Flame spraying; Fluid dynamics; Hydrodynamics; Mathematical models; Melting; Metals. Metallurgy; Nozzles; Oxygen; Powder metallurgy. Composite materials; Production techniques; Sprayers; Sprays; Technology; Wire; Fluid dynamics; Flow(fluid); HVOF spraying; Hot spraying; Modeling; Velocity; Surface treatment; Deposition process; Torch
• ISSN: 1059-9630; 1544-1016
• DOI: 10.1361/105996398770350855

The fluid and particle dynamics of a high-velocity oxygen fuel (HVOF) thermal spray torch are analyzed using computational and experimental techniques. Three-dimensional computational fluid dynamics (CFD) results are presented for a curved aircap used for coating interior surfaces such as engine cylinder bores. The device analyzed is similar to the Metco diamond jet rotating wire (DJRW) torch. The feed gases are injected through an axisymmetric nozzle into the curved aircap. Premixed propylene and oxygen are introduced from an annulus in the nozzle, while cooling air is injected between the nozzle and the interior wall of the aircap. The combustion process is modeled using a single-step, finite-rate chemistry model with a total of nine gas species which includes dissociation of combustion products. A continually fed steel wire passes through the center of the nozzle, and melting occurs at a conical tip near the exit of the aircap. Wire melting is simulated computationally by injecting liquid steel particles into the flow field near the tip of the wire. Experimental particle velocity measurements during wire feed were also taken using a laser two-focus (L2F) velocimeter system. Flow fields inside and outside the aircap are presented, and particle velocity predictions are compared with experimental measurements outside of the aircap.