10 - Supersonic jet/substrate interaction in the cold spray process

Abstract

Publisher Summary Despite extensive investigation of jet gas dynamics, some issues have not been adequately studied. There are many aspects of this problem, and, with respect to cold spray, one of the most important tasks is to increase the particle velocity as high as possible. The development of the boundary layer on the nozzle walls, the structure and stability of the jet in different exhaust modes, interaction of a supersonic jet with the substrate, and heat transfer between the jet and the substrate, should be studied to obtain the optimal velocity and temperature of a particle at the moment of its impact onto the substrate surface. At present, a wide spectrum of research in the field of gas dynamics of the cold spray process has been conducted. Various aspects of this problem have been considered, including the nozzle shape optimization. The gas dynamics of jets exhausting from conical nozzles with circular cross-sections, that is, symmetrical axis flows, has been examined in detail. An analysis of the features of such jets, as applied to the cold spray method, revealed that the use of nozzles with rectangular cross-sections is also promising.