CFD simulation of metal cold spray process

• Main Author: Kamaraj, Aravinth
• Other Authors: Zhou Wei
• Format: Theses and Dissertations
• Language: English
• Published: 2018
• Subjects: DRNTU::Engineering::Mechanical engineering
• Online Access: http://hdl.handle.net/10356/75920
• Institution: Nanyang Technological University

Numerical study of cold spray is required for optimizing performance and process parameters and design of nozzle and powder injector for spraying metals onto the surface. The objective of this dissertation is to study and review the principles and existing modelling techniques for the Metal Cold Spray using Computational Fluid Dynamics (CFD) to understand the influence of the direct process parameters (i.e. pressure, velocity and carrier gas composition) and how it affects the particles that are sprayed on to the substrate. This work describes a detailed study of CFD approach and carrier gas composition and how it affects the average particle velocity. A model of 3-dimensional nozzle with chamber and particle injector was used to generate the flow field of particles(Ti6Al4V) with help of compressed carrier gas such as nitrogen, helium at supersonic speed. Particles are dragged by the carrier gas up to high velocity magnitudes, resulting in plastic deformation process upon impact with a solid substrate positioned at specific standoff distance. It has been found experimentally that the Ti6Al4V has suitable bonding properties when it comes to cold spray application. An optimum average particle velocity is found using Computational Fluid Dynamics for various compositions of carrier gas for a given particle size distribution. The computational domain is analyzed for the real time scenario of boundary conditions and results are plotted.