Metal additive manufacturing (AM) is an evolving technology, and the supply of quality feedstock material needs to follow suit. Closed-coupled optimized-pressure gas atomization (CCOPGA) promises narrow size distribution, spherical powder, and optimized use of gas. However, pour-tube melt solidification is an obstacle to enabling a wider alloy palate. Many solutions involve adding melt superheat, but do not account for all cooling influences. While the Joule-Thomson effect and forced convection promotes high cooling rates for the powder, excessive heat loss can lead to freeze-off. Therefore, optimizing the melt delivery geometry is needed to reduce freeze-off and down time. Analytical and numerical models are employed to study the heat transfer process between the pour tube and the surroundings for CCOPGA of both Ni and Ca melts. The effects of normalized length, radius, and thermal diffusivity are considered. Work supported by USDOE-EERE-AMO and USDOE-OE through Ames Laboratory Contract No. DE-AC02-07CH11358.