Characterization of H2O vapor transport through lunar mare and lunar highland simulants at low pressures for in-situ resource utilization

Abstract

H2O(v) transport through packed beds of lunar mare and lunar highland simulants was examined for relevant in-situ resource utilization conditions to inform volatile H2O extraction from the lunar surface. Experiments were conducted with different packed beds at average bed pressures of 105 and 3,960 Pa at ∼ 350 K for different flow regimes in the range of 0.47 <Kn¯ < 20.7. A piecewise model was used to describe the transition between the advective flow regime and the Knudsen flow regime. Non-linear regression was used to determine a tortuosity shape factor of 2.6175 ± 0.0092 and 0.0937 ± 0.0008, a transition Knudsen number of 1.5984 and 4.0995, and a viscous flow permeability of 0.8238 ± 0.0010 × 10-12 m2 and 5.4805 ± 0.0061 × 10-12 m2 for the lunar mare and lunar highland simulants, respectively. The resulting Knudsen diffusivities were 6.6530 ± 0.0018 cm2·s−1 and 18.9008 ± 0.0100 cm2·s−1, respectively. These results are necessary for informing the development of in-situ resource utilization technologies for the thermal extraction of H2O.