2019-06-202019-06-202019-07-07ICES_2019_220https://hdl.handle.net/2346/84443John Brooker, National Aeronautics and Space Administration (NASA), USADan Dietrich, National Aeronautics and Space Administration (NASA), USASuleyman Gokoglu, National Aeronautics and Space Administration (NASA), USAGary Ruff, National Aeronautics and Space Administration (NASA), USADavid Urban, National Aeronautics and Space Administration (NASA), USAICES509: Fire Safety in Spacecraft and Enclosed HabitatsThe 49th International Conference on Environmental Systems was held in Boston, Massachusetts, USA on 07 July 2019 through 11 July 2019.Computational fluid dynamics (CFD) simulations of flows inside a spacecraft offer a high level of detail and fidelity and are invaluable tools in the design of spacecraft environmental control and life support systems (ECLSS). They are, however, time and resource intensive and not efficient for large scale sensitivity analyses over a range of possible design parameters. Lumped capacity analysis (LCA) treatments are simple and fast, but lack the detailed treatment of flow and heat transfer that CFD simulations offer. Their speed and low level of required resources, however, make them more convenient for large sensitivity analyses. Both approaches have the potential to be design tools to assess the impact that an accidental fire will have on a spacecraft. This paper compares the results of CFD and LCA simulations for a given volume approximately the size of the Orion spacecraft. The CFD model uses the open source Fire Dynamics Simulator for the simulation and includes, as sensitivity parameters, changes in ECLSS ventilation (direction and speed), fire location, and wall boundary condition. The results show that the LCA model can reasonably predict pressure rise in a spacecraft if the prescribed fire scenario approximates the model assumptions. The sensitivity studies show how variations in parameters not captured directly in the LCA model (e.g., direction of ventilation flow) influence the results and provide limits on the predictive capability of the LCA. We also demonstrate how CFD simulations can improve LCA predictions by providing more realistic estimates of heat transfer coefficients between the gas and various cabin walls.application/pdfengSpacecraft fire safetyComputational fluid dynamics modelLumped capacity modelPresentations