A computer code which models the transient behavior of liquid metal heat pipes from startup to steady state operation has been developed. The code solves the area-averaged Navier-Stokes equations for four components (solid, liquid, and gaseous lithium and a noncondensible gas) with a fully implicit temporal discretization. An auxiliary model for radial and axial interphasic heat and mass transfer and two models treating the capillary surface characteristics are developed. The effects of radial mass injection on the fraction of the flow and diffusion are included.
The influence of the evaporation/condensation accommodation coefficients on code run results was found to be large. The code could satisfy each of several experimental criteria separately, but not concurrently, using spatially constant coefficients. Further experimentation into the nature of these coefficients is dictated.
Code runs have been conducted which begin with the last pipe frozen and model the radial and axial progression of the melt front, ultimately reaching steady state operation. The incorporation of diffusion and alternate friction correlations was found to have little effect on overall heat transfer.
