Numerical Simulation of Toilet System Air Flow Characteristics in the International Space Station

The goal of the study is to verify the air circulation characteristics and interaction of the new Toilet System (TS) in the Node 3 module of the International Space Station. Results of Computational Fluid Dynamics (CFD) TS airflow analysis are presented. The TS geometry model consists from the Waste and Hygiene Compartment (WHC) and Universal Waste Management System (UWMS) areas with modifications to fit in the cabin. The privacy protection bump-outs, stall of the WHC and UWMS, as well as some internal equipment, are included in the present modeling. Crewmember models, ECLOIDs, are used in the analysis. Various ventilation scenarios are considered. Velocity distributions for the nominal ventilation of the redesigned TS are analyzed with regard to the TS cabin air velocity requirements. Off-nominal ventilation regimes when CCAA fan, IMV ventilation and WHC avionics fan are off are under study. The ability of the redesigned TS to supply crew hygiene activities is discussed.