Research And Device Design On Coaxial Powder Flow In Laser Cladding

With modern production on the material properties unceasing enhancement, the rapid development of laser processing technology, laser cladding has become material surface modification, preparation of new materials and broaden the scope of application of traditional material important means one. Laser cladding coaxial send powder conveying, laser beam, powder when protecting gas supply synchronously, which can effectively improve the quality of the cladding layer and powder utilization, therefore coaxial send powder nozzles of research and design is currently of laser cladding material supply equipment hotspot.In this paper to probe coaxial send powder spray nozzle structure and send powder, based on the mechanism of the effect of each factor to feed powder quality, using computational fluid dynamics CFD method to send powder flow field, the numerical simulation study in many cases of gas-solid two-phase flow field, powder trajectory, powder focused concentration and focus radius rate, and designs a vertically remove focus tunable laser coaxial send powder nozzles. Paper based on the structure of coaxial send powder nozzles, study the characteristics of the collision in powder nozzles gas powder two phase flow process, the computation method of combining the laser coaxial send powder drag force model actual situation correction, write custom function calls to Fluent adjuant calculation; Establish gas powder two-phase flow physical model, adopt euler double fluid theory and algorithm of gas-solid two-phase flow field based on comprehensive study of different impact conditions of jet focus effect coaxial powder are analyzed and the powder concentration distribution focus, focus radius, focal length size, the results of the study show that, powder flow injection speed main influencing powder focus concentration and focus to the nozzle of the distance; Nozzle gap mainly affect powder after focusing focus diameter; Powder, the greater the powder mouth tilt the down stream focus; Send powder content on powder flow concentration distribution, also has little influence of various parameters influence each other, need reasonable allocation in order to improve the quality of the cladding.Based on the simulation results, and combining the current coaxial send powder structure design the insufficiency, design a kind of coaxial send powder nozzles and analyses the simulation analysis, powder flow field stable, realize the powder, and can focus adjustable for gravity to feed powder and the carrier gas to feed powder, the design of structure of vertical remove and replace convenient nozzle ends, equipment, can meet the further generality high requirements of laser coaxial send powder for further equipment, provides the theory basis for trial.