Design And Numerical Optimization Of Lateral Powder Nozzle For Broad Beam Laser Cladding

With the popularization of high powder lasers and the spreading of technology of broad beam laser cladding, its applications become more and more broader. In the technology of broad beam laser cladding, wide-band lateral powder nozzle is one of the key technology to achieve broad beam laser cladding. When the lateral powder nozzle is working, it can produce a bunch of wide-band powder which is continuous, stable and homogeneous. As the powder is sending to the laser action area, it can improve the quality of laser cladding and the effective utilization of powder. So we have taken a lot of efforts at the research and design of wide-band lateral powder nozzle as a type of feeding equipment for the material of broad beam laser cladding.In this paper to probe into the structure of wide-band lateral powder nozzle and the theory of powder feeding, I have designed a type of wide-band lateral powder nozzle which the width of feeding powder can be changed. Combined with the structure of flow field of wide-band lateral powder nozzle, a physical model about gas-solid two phase flow is established. and a numerical simulation is taken with the Discrete model and Renormalization-group (RNG) k-ε model to make a comprehensive investigation on gas-solid two-phase flow.Aimed at each factors which affect the result of powder feeding, paper use computational fluid dynamics CFD method to simulate the flow field so that the track of the powder and the distribution of powder concentration can be observed. There are many factors affecting the distribution of powder concentration. When the angle between nozzle and horizontal direction is 75°、65°and 55°,the number of powder inlets is 2、3、and 4,the inclination angle of nether flow channel is 40°、45°and 50°,and the height of chute is 20mm、30mm and 40mm,the powder concentration distribution is measured on the plane which is below the outlet of powder about 20mm. Different models have different situation of powder distribution, then the best model is selected by the homogenization of powder concentration distribution.Based on the optimized result of simulation, and combined with the shortage of current wide-band powder nozzles, a type of wide-band powder nozzle which the width of feeding powder can be changed is designed to meet the different width of fecula. A feeding powder experiment was conducted on the nozzle, adjusting the width of outlet 12mm, finding that the result of the experiment in accord with the numerical simulation. Different widths of powder outlet have also been performed, finding that the homogeneity of powder mass distribution and the effective utilization of powder meet requirement of laser cladding. It can provide support for the broad beam laser cladding experiment.