The performance of close-coupled gas atomization of liquid metals depends on flow conditions, geometry, and fluid properties. Two important parameters influencing particle size distribution are the gas-to-liquid mass and momentum flux ratios. The gas-to-liquid coupling is inherently linked to the atomization gas die design (with discrete jets) and melt pour-tube tip geometry. Therefore, a better understanding of coupled flow and geometric effects can impact the criteria employed in die and pour-tube tip design. We have explored numerically the effect of parameters, e.g., gas die dimensions and apex angle, on the gas flow and particle size distributions for fixed molten aluminum and nitrogen gas flow conditions. These parameters affect the efficiency of close-coupled gas atomization. Conditions of high coupling tend to reduce particle sizes. This study employs a multiphase compressible 5-equation model in two dimensions (Cartesian).