Simulation and experimental research based on carrier gas flow rate on the influence of four-channel coaxial nozzle flow field

Shi Rui Guo,Bo Zheng,Yan Long Cao,Lu Jun Cui,Ying Hao Cui,Xiao Lei Li,Qian Qian Yin,Wen Han Zeng

doi:10.1177/0020294020964232

Abstract

This paper investigates the influence of carrier gas flow on the external flow field of coaxial powder feeding nozzle. FLUENT software was adopted to establish gas-solid two-phase flow. The simulation of powder stream field under different carrier gas flow was also carried out. Results show that the larger the flow of carrier gas is, the higher the gas flow field velocity at the nozzle outlet is. At the same time, the concentration at the convergence point is lower, and the convergent point is maintained at 0.015 m. Under the condition of 4 L/min, the powder flow convergence is good. When it exceeds 4 L/min, powder spot diameter increases. The experiment of powder aggregation and laser cladding forming were completed, which shows that the forming effect is the best one under the condition of 4 L/min. It is consistent with the simulation analysis results and has a high reference to the optimization of the process parameters of coaxial nozzle.

Highlights

Laser cladding (LC) is a surface repair technique which exhibits many advantages.[1,2] For instance, the hardness is high,[3] the substrate has little deformation,[4] the dilution rate is low and the wear resistance shows well.[5]
The information of the flow field can be completely analyzed by numerical simulation in the model calculation domain
With a certain amount of powder feeding, there is a simulation about the flow field of powder when the carrier gas flow was respectively 2–10 L/ min(Many experimental procedures have proved that when the carrier gas flow rate is less than 2 L/min, the powder flow is blocked due to insufficient air force or scattered at the nozzle, and the convergence is poor; when the carrier gas flow rate is too large, the cladding layer is too thick, which is inconsistent with the actual process and the powder utilization rate is extremely low, so only consider 2–10 L/min), and the effect of carrier gas flow on the external flow field of powder feeding by the four-channel nozzle was obtained

Summary

Introduction

Laser cladding (LC) is a surface repair technique which exhibits many advantages.[1,2] For instance, the hardness is high,[3] the substrate has little deformation,[4] the dilution rate is low and the wear resistance shows well.[5]. Carrier gas flow affects the concentration, velocity, and the distribution of particle, results in affecting the powder flow aggregation characteristics.

Results

Conclusion