Three-dimensional K-ε Turbulent Model of Weld Pool in GTAW Process

摘要

A two-equation K-ε turbulent fluid flow model is built to study the heat transfer and fluid flow in GTAW molten pool of the stainless steel. This model combines the buoyancy force, lorentz force and marangni force as driving forces of the fluid flow in the weld pool. The simulating results show that the molten metal flows outward mainly caused by the marangoni convection, which makes the weld pool become wider and shallower by this transport. The temperature gradient on the weld pool surface increases when the input energy enhances, which causes the velocity of the molten metal and the quantity of the weld pool geometry increase too. The thermal diffusivities on the weld pool are discussed. The predicted weld pool geometry and the thermal distribution of the weldment are compared with the experimental results and good agreement is gotten between the experimental and K-ε turbulent fluid flow model results.