Open AccessВплив діаметру частинок порошку нікелю на їх швидкість і температуру при холодному газодинамічному напилюванні
Author(s) -
Олександр Володимирович Шорінов,
Сергій Олександрович Поливяний
Publication year - 2021
Publication title -
avacìjno-kosmìčna tehnìka ì tehnologìâ/avìacìjno-kosmìčna tehnìka ta tehnologìâ
Language(s) - English
Resource type - Journals
eISSN - 2663-2217
pISSN - 1727-7337
DOI - 10.32620/aktt.2021.4sup1.15
Subject(s) - nozzle , mechanics , materials science , gas dynamic cold spray , particle velocity , particle (ecology) , critical ionization velocity , particle density , flow velocity , flow (mathematics) , volumetric flow rate , particle size , coating , thermodynamics , composite material , chemistry , physics , oceanography , volume (thermodynamics) , geology
To deposit coatings in cold gas-dynamic spraying (CS), a high-speed gas flow is used to accelerate and heat particles. Therefore, first of all, it is necessary to consider the general laws of the gas flow and the movement of particles in the flow, as well as its interaction with the substrate. Due to the CS process depends primarily on the particle velocity, it is important to understand the effect of the process parameters (pressure and temperature at the nozzle inlet), the characteristics of the powder particles (material density, shape, and size), and the geometry of the nozzle. The gas velocity limits the particle velocity that can be achieved with the CS process. Utilization of high gas pressure, long nozzles, and small particles lead to the fact that the particles move at a velocity close to the velocity of the gas, which can be increased by using gases with low molecular weight, as well as heating it. As a result of the analysis of theoretical and experimental methods for studying the cold spraying process, it was found that for coating formation velocity of powder particles needs to obtain a certain value (critical velocity), which depends on particle temperature at the impact, and density of the particle material. Numerical simulation of gas dynamics of a two-phase flow in CS nozzle and at the outlet from it for the range of air temperatures from 573 K to 873 K and constant pressure of 1,0 MPa has been carried out. The influence of the diameter of nickel powder particles on their temperature and velocity at impact was investigated. Numerical simulations were performed for a range of particle diameters from 5 to 30 μm. In the future, the results obtained can be used to find the optimal size of the powder particles under certain spraying conditions, to calculate the critical particle velocity, and also to develop the window of deposition. This will make it possible to select the optimal parameters of the gas flow at the nozzle inlet (pressure and temperature), which are guaranteed to ensure the adhesion of particles to the substrate and the formation of coatings. Also, the results obtained can be used to predict the properties of coatings, as well as to achieve maximum deposition efficiency of the CS process.