Numerical simulation of a porous plate water sublimator working in the periodic mode and analytical study of its evaporation process

A water sublimator is a thermal control device that uses the phase change latent heat of water for heat rejection in space. It can allow effective heat dissipation in a microgravity environment. Existing models of water sub-limators mainly focus on numerical simulations and do not calculate the temperature distribution and phase change interface position accurately. Furthermore, very few theoretical studies have been conducted. This study investigates a porous plate water sublimator, establishes the governing equations of each stage of a sublimator working in the periodic mode, and performs discrete calculations using the finite volume method. Additionally, a dimensionless analysis of the governing equations is conducted, and the flow in the evaporation process occurring in the porous plate is solved analytically. The results show that the sublimator enters a stable state after several periods. The effects of the thickness and pore diameter of the porous plate, feedwater pressure, and the type of working fluid on the evaporation process are discussed. It was observed that a large pore diameter and high feedwater pressure resulted in a rapid rise in the liquid level in the porous plate. An adaptive mesh method is used to induce a change in the length and number of meshes in accordance with the interface movement, thereby solving the problem caused by changes in the calculation domain. Moreover, an analytical solution of the evaporation process in the porous plate is provided, and it has universal significance for describing similar phenomena.