Questions About the 0 and Constant Folders

[puente-tamu]

Hello, I have a few questions to ask for clarity on the simulation. I would greatly appreciate an answer to each. Thank you in advance to the team. Also, please correct any misconceptions I have.

1. For LPBF/EPBF, what is the significance between choosing 100% solid or 100% powder? Could I simulate with just 100% solid and get good results from ignoring the powder phase? Do the transport properties in the powder phase matter if I choose 100% solid?

2. In the constant/transportProperties file:

//- fluid flow properties
rho     [1 -3 0 0 0 0 0]    7569.92;   // reference density
mu      [1 -1 -1  0 0 0 0]  0.003032;  // dynamic viscosity
beta    [0 0 0 -1 0 0 0]    1.2e-4;    // coefficient of thermal expansion
DAS     [0 1 0 0 0 0 0]     10e-6;     // dendrite arm spacing (for drag)
Lf      [0  2 -2  0 0 0 0]  2.1754e5;  // latent heat of fusion

What is a "reference" density? Is it at room temperature or is it a good value to consider/approximate the density of the material at elevated temperatures? In other words, for LPBF/EPBF, would it be at room temperature or a value somewhere between the ambient/preheat and melting/liquidous temperatures?

3. In the constant/transportProperties file, should I select a coefficient of thermal expansion (beta) value at room temperature or somewhere between the ambient/preheat and melting/liquidous temperature?