Investigation of enhanced vortex tube air separators for advanced space transportation

Experiments have shown that a vortex tube can be used to separate oxygen and nitrogen from air. If oxygen can be collected at sufficiently high purity and yield, the vortex tube may be used in an on-board liquid oxygen collection system for rocket-propelled vehicles. Trade studies indicate that a feasible vortex tube for low-Earth-orbit launch applications must produce oxygen at a minimum 90% purity and 90% yield. Various investigations have shown that separation occurs, but none have yet demonstrated the performance necessary for a vortex tube to be considered as the primary technology for a rocket oxidizer collection system. The purpose of the present research program is to validate the experimental results of prior research and to test vortex tube enhancements theoretically capable of increasing oxygen purity and yield to a useful level. To date, peak oxygen purities of 97% have been achieved at low yields, as well as purities up to 80% at yields up to 25% and purities up to 60% at yields up to 40%. Details of the ongoing experimental effort are presented.