Non- Fourier Heat Transfer and Fluid Flow Simulation in Keyhole Plasma Arc Welding Process

To obtain the transient temperature in different parts of the body and the welding pool growing, the continuity and momentum equations are solved along with the energy equation. The analysis for a rectangular plate made of AISI 304 Stainless Steel is done by writing a program with Fortran.90. Because the Fourier heat transfer equation at short times and large dimensions does not have sufficient accuracy a non-Fourier form of heat transfer equation is being used. Gaussian heat source is considered as a heat source model. The governing equations for fluid flows are solved by the finite volume method in which the SIMPLE method is used for calculating pressure-velocity coupling in fluid flows, likewise the Power-Law method and the staggered grid can be used for discretization equations. The finite difference method is also used to solve the energy equation. The effect of heat conduction, fluid flows and force actions at the weld pool is considered. Thermo-physical properties such as thermal conductivity, specific heat and dynamic viscosity are a function of temperature. There are two mechanisms, radiation and convection heat transfer, which actively cause heat transfer to the surroundings. The numerical results were compared with experimental data. Finally, the results obtained from the assumed Fourier heat transfer are compared for the same study. The results bear the fact that the weld pool thick in the cross section of keyhole PAW and the time that molten metal reaches to the end of thick metal, are in good agreement compared to experimental measurements.