CFD Analysis Results for CO2 Washout in the Exploration Space Suit

An Exploration Space Suit has been modeled using computational fluid dynamics to evaluate options for the orientation and location of the fresh vent gas inlet that provides CO2 (carbon dioxide) washout. A transient, multi-species, sinusoidal breathing model was employed to simulate breathing. Several options were presented which used various methods to aid in washout with the best results coming from what was described as the Tri Vents configuration. Several geometric and metabolic perturbations were imposed on the baseline Tri Vents model to determine the sensitivity of the solution. Turning the head 45° had a similarly negative impact to CO2 washout as breathing primarily out of the mouth. Tipping the head forward was beneficial as it put the face closer to the refreshed gas, while tipping the head forward and pressing the chest against the front of the suit had marginally worse results. Three different metabolic rates were explored and the relationship between metabolic rate and CO2 washout performance was determined.