Dynamics of Gas Evacuation from a Honeycomb Structure Having Common Wall Perforations

摘要

A model has been developed to provide insight regarding the time to evacuate gas from a sealed structurenconsisting of elongated hexagonal cells for which the common walls share a relatively small pinhole. Gas flow fromansingle cell to a vacuum environment, and then between two connected cells, is first considered. The analysis is thennapplied to a linear string of attached cells, where the pressure drop from the center cell through the edge cell as anfunction of time and number of intermediate cells is evaluated. Both adiabatic and isothermal conditions wereninvestigated, with the latter resulting in faster drain times. A scaling relationship of the pressure drop between timenand the number of cellswas found and used to extend themodel to themore complicated, two-dimensional hexagonalnarray problem. Considering an array based on a typical common bulkhead geometry, and applying the isothermalncondition, a best-case evacuation time for argon was predicted.