Powder flow field distribution with different parameters in coaxial laser cladding

Abstract

A numeric model of velocity and concentration distribution of shield gas-metal powder two phases flow field output by nozzle in laser cladding is established, and it is calculated by FLUENT software. In this model, the influences of momentum and mass transmission in the two phases flow are taken into consideration. The analysis on metal powder flow field velocity and concentration distribution with different process parameters (nozzle exit width w, initial gas flow velocity u and initial powder concentration c at nozzle entrance, angle of inward and outward wall of nozzle α, Φ) is conducted. The calculated results show that w mainly affects concentration and velocity magnitude, u mainly affects the focused position and velocity magnitude, c mainly affects concentration magnitude, α and Φ mainly affects the focused position and concentration magnitude. Under the process parameter conditions: w=1mm, c=0.1, u=3m/s,α=82 ° , Φ=68.5°, the same flow field is measured with DPIV technique. The calculated result agrees with the measured result, which indicates that the established model is reliable. The model can be used to understand the influences with different flow field process parameters and further design the nozzle size.