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

中线有限公司是一家私人控股的温莎，安大略，为汽车，航空航天和国防工业提供先进的生产技术。CenterLine生产商用超音速冷喷涂系统，这是一种高速材料沉积工艺，其中小的未熔化的粉末颗粒（直径通常为10 - 50 µm）通常在压缩气体的超音速射流中加速到200至1000 m/s之间的速度。在与目标表面撞击时，固体颗粒变形并结合在一起，迅速形成沉积材料层。Centerline正在考虑将这项技术扩展到增材制造的可能性。 增材制造是一种三维（3D）打印工艺，其构建层以从数字模型创建实体对象。这个过程是通过使用3D计算机辅助设计（CAD）来创建一个数字模型来实现的，该模型被切成非常薄的横截面，称为层。在打印过程中，3D打印机会建立连续的材料层，直到物体完成。相比之下，传统的制造技术或减材制造涉及通过切割或钻孔从块体形状系统地去除材料。与传统制造方法相比，增材技术在许多应用中具有优势。零件可以形成任何几何复杂性。 CenterLine现有的冷喷涂喷嘴提供约4.0 mm的点尺寸。为了获得更好的制造分辨率和生产复杂的物体，需要将点尺寸减小到1.0 mm或更小。通过按比例缩小当前的德拉瓦尔喷管设计，可以达到这一目的。考虑到商业化的潜力，CenterLine希望对类似于更小喷嘴组件的模型的流体流动特性进行数值评估。将在温莎大学进行详细的计算流体动力学（CFD）研究，以评估收敛-扩张喷管（de拉瓦尔喷管）的性能。

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).