Design of de Laval nozzle for additive manufacturing and 3D printing

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CenterLine Ltd. is a privately held Windsor, Ontario, based corporation, providing advanced production technologies to the automotive, aerospace and defence industries . CenterLine produces commercial supersonic Cold Spray Systems, which is a high-rate material deposition process in which small, non-melted powder particles (typically 10 - 50 µm in diameter) are normally accelerated to velocities between 200 to 1000 m/s in a supersonic jet of compressed gas. Upon impact with a target surface, the solid particles deform and bond together, rapidly building up a layer of deposited material. Centerline is considering the possibility of extending this technology to additive manufacturing. Additive manufacturing is a three-dimensional (3D) printing process that builds layers to create a solid object from a digital model. The process is achieved by using a 3D computer-aided design (CAD) to create a digital model that is sliced into very thin cross-sections called layers. During the print process, the 3D printer builds up successive layers of material until the object is finished. By contrast, the traditional manufacturing techniques or subtractive manufacturing involve the systematic removal of material from bulk shapes by cutting or drilling. Additive technologies offer advantages in many applications compared to the traditional manufacturing methods. Parts can be formed with any geometric complexity. CenterLine's existing cold spray nozzle offers a spot size of about 4.0 mm. It is required that the spot size be reduced to 1.0 mm or less for a better manufacturing resolution and for producing intricate objects. It may be possible to achieve this objective by scaling down the current de Laval nozzle design. Considering the potential for commercialization, CenterLine would like to evaluate numerically the fluid flow characteristics of a model that resembles a much smaller nozzle assembly. A detailed computational fluid dynamics (CFD) investigation, will be carried out at University of Windsor to assess the performance of the convergent-divergent nozzle (de Laval nozzle).