Numerical modeling of liquid cold spray process

Liquid cold spray (LCS) is an innovative process for coating deposition, part restoration and solid-state additive manufacturing. In this technique, high-speed superheated liquids that are much denser than typical gases used in conventional cold spray (CS) systems are used to propel solid particles (can be larger than 60 µm) to supersonic velocities. Pressurized water (in the range of 300 and 500 MPa) travels through a high-pressure tubing which is heated to approximately 200-300 °C. Then, the water passes through an orifice to enter the mixing chamber. Due to a rapid depressurization process, flash boiling occurs inside the chamber and a portion of water evaporates. The metal particles are injected into the mixing chamber. The mixing chamber is connected to a converging nozzle to accelerate the multiphase flow towards the substrate. In the present study, the modeling of flash boiling flow inside the chamber as well as the multiphase flow inside and outside the nozzle are presented. A 2D axisymmetric domain and a mixture model are utilized. Different phase change models are tested to find the most relevant one for the LCS process. The pressures inside the mixing chamber obtained from numerical simulations are compared and validated against the experimental results.