A CFD-Based Procedure for Evaluation of Ventilation of a Suddenly-Opened Closeout Space and Its Application to the International Space Station

The aim of the study is to understand risks associated with a crew member accessing behind the closeout panel or space. Since there is a possibility that a particular closeout space is filled with a harmful gas mixture that is different from the cabin atmosphere, the time needed to ventilate this space should be evaluated. The three-dimensional Computational Fluid Dynamics (CFD) model developed for prediction of time-dependent turbulent flow and concentration fields inside and near a suddenly-opened box is described in the paper. Several cases with different positions of the closeout space, initially filled with pure oxygen, are analyzed under the U.S. Laboratory (USL) ventilation conditions. A simplified flow model, where a suddenly-opened box is ventilated by uniform external throughflow, is considered as well. Parametric computations performed for this case has resulted in a special procedure for quick evaluation of the closeout-space purging process, using solely the steady-state ventilation velocity distributions, computed previously for the USL module.