3. Flow technology (gas + powder)

Given the very principle of the cold spray process, knowledge and control of the multi-phase flow - in this case gas + powder particles - which defines it, are of prime importance. On the one hand, these two aspects involve optimizing the design and manufacture of nozzles, the heart of which is the Laval nozzle (convergent-divergent). On this basis, their geometry can be very diverse and complex (§ 3.1 ). On the other hand, flow simulation is crucial to understanding the process, insofar as particle kinematics and fluid dynamics, in this case spray gas, are governed by phenomena that cannot be directly observed,...