Study of ice formation in ducts for space use via fluid dynamics simulation

This thesis work deals with the study of the formation and growth of ice on the Pressure Control Assembly (PCA), a pressure control valve that will be installed on board the I-HAB module of the future Lunar Gateway mission. The lunar space station, which will constitute a huge step forward towards interplanetary exploration, has its roots in the International Space Station, and therefore the study of the latter's Environmental Control and Life Support Systems (ECLSS) is fundamental, in order to understand the technological evolution and to prevent critical issues encountered in the past. After an analysis of the methodologies present in the literature to establish a valid ice formation model and using the Ansys Fluent software, we will proceed with the analysis of the geometry of the PCA and the parametric study of the mesh associated with it. One of the main objectives is to establish whether it is possible to consider removing the radiator installed on the PCA, in order to obtain significant energy savings. Additionally, this work aims to improve ice formation modeling in space environments, topic that has been scarcely explored so far. The study will be carried out a priori and involves the creation and interpretation of the phase diagram, evaluating the distribution of the thermodynamic state on the valve during an adiabatic depressurization. The presence of water is possible due to the humid air inside the module, which can lead to condensation and subsequent ice formation. If at the end of the depressurization solid phases are present, there will be the possibility of ice growth, depending on the interaction with the wall, while if there are gaseous or liquid phases this possibility is not present. The work provides useful indications for the design of the Pressure Control Assembly, contributing to improving the thermal efficiency of the I-HAB module.