PSI - Issue 69

Mohammadjavad Abdollahzadeh et al. / Procedia Structural Integrity 69 (2025) 2–19

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Table 1: Material Properties Considered in the simulation [48, 52-54]

Liquid Properties

Parameters and Properties Specific Heat Density VS Temp Thermal Conductivity VS Temp Viscosity VS Temp Surface Tension VS Temp

Values (Unit) 840 J/Kg/K

Figure (3) Figure (3) Figure (3) Figure (3)

Solidification Properties

Solidus temperature Liquid Temperature Latent heat of fusion

1554.59 K 1582.89 K 2.0e+05 J/Kg

Solidified Properties (Austenite phase properties)

Density Specific Heat Thermal conductivity

6450 Kg/m^3 840 J/Kg/K 18 W/m/K

Evaporation Properties

Latent heat of vaporization

7.6e+06 J/Kg

2.3. Governing Equations for Thermal and Fluid Flow Simulation When subjected to a laser beam of sufficient intensity, the targeted powder experiences a phase transition, transitioning into a molten state. The fluid dynamics of the liquefied material within the melt pool can be characterized utilizing the Navier-Stokes equation. The Volume of Fluid (VOF) methodology is deployed to determine the free surface [55]. By invoking the principles of conservation of mass, momentum, and energy, one can explain the fluid flow and heat transfer dynamics within the melt pool. The continuity equation can be expressed as follows [32, 33, 35, 41, 56-58]. ! ! " (uA " )+ ! ! # &vA # (+ ! ! $ (wA $ )=0 (1) In Eq. (1), the velocity variables along each axis in Cartesian coordinates are denoted by the respective terms u, v and w. Additionally, the fractional area open to flow in each respective direction is symbolized by A x , A y , and A z . The subsequent equations present the general form of the momentum equations [32, 33, 35, 41, 56-58]. ! ! % & + ( ' ! ,uA " ! ! % " +vA # ! ! % # +wA $ ! ! % $ -=− ) '! ! * " +G " +f " −b " (2) ! ! + & + ( ' ! ,uA " ! ! + " +vA # ! ! + # +wA $ ! ! + $ -=− ) '! ! * # +G # +f # −b # (3) ! ! , & + ( ' ! ,uA " ! ! , " +vA # ! ! , # +wA $ ! ! , $ -=− ) '! ! * $ +G $ +f $ −b $ (4) In the equations, G x , G y , and G z symbolize body accelerations such as gravity. Moreover, ρ signifies density, P represents pressure, and t denotes time. The variables f x , f y , and f z are indicators of viscous accelerations, while b x , b y , and b z are representative of flow losses in porous media. Viscous acceleration terms can be defined as follows [57].