Numerical and experimental study on the heat and mass transfer of porous plate water sublimator with constant heat flux boundary condition

Water sublimators offer effective heat rejection for the spacecraft, which work in warm environments or with peak heat loads, by evaporating or sublimating water into the vacuum. In this study, the heat and mass transfer of porous plate water sublimator with constant heat flux boundary condition was investigated numerically and experimentally. The startup process of sublimator was divided into three continuous states to analyze its work characteristics: water evaporation in the feed water gap state, water evaporation in the porous plate state and the alternation of evaporation and sublimation in the porous plate state. The locations of evaporation/sublimation front and freezing/thawing interface in the micron porous plate associate with the rarefied water vapor flow through the porous plate were taken into consideration. The heat and mass transfer equations coupling with phase change and rarefied gas flow through the porous plate were established and solved to evaluate the sublimator temperatures, water and vapor mass flow rates, locations of phase change interfaces. In addition, experiments of a water sublimator test module were conducted to validate the numerical model. The experimental results obtained were consistent with the simulation results.