Reclamation and re-use of water is critical for space-based life support systems. A number of functions must be performed by any such system including removal of various contaminants and oxygenation. For long-duration space missions, this must be done with a compact, reliable system that requires little or no use of expendables and minimal power. DynaJets cavitating jets can oxidize selected organic compounds with much greater energy efficiency than ultrasonic devices typically used in sonochemistry. The focus of this work was to develop cavitating jets to simultaneously accomplish the functions of oxygenation and removal of contaminants of importance to space-structured water reclamation systems.

The innovation is a method to increase the concentration of dissolved oxygen or other gasses in a liquid. It utilizes a particular form of novel cavitating jet operating at low to moderate pressures to achieve a high-efficiency means of transporting and mixing the gas into the liquid. When such a jet is utilized to simultaneously oxygenate the liquid and to oxidize organic compounds within the liquid, such as those in waste water, the rates of contaminant removal are increased.

The invention is directed toward an increase in the dissolved gas content of a liquid, in general, and the dissolved oxygen content of a liquid in particular. Liquid at moderate pressure is forced into a DynaSwirl swirl chamber in which a central vortex is formed that has a core pressure lower than the vapor pressure of the liquid, thus inducing cavitation in the vortex into which the desired gas(es) are drawn or injected. The cavitation is then ejected from the nozzle through the exit orifice into a volume of liquid where the cavities break up and collapse. The large cavity surface area and violent mixing due to cavity collapse are believed to facilitate gas transport and dissolution into the liquid. These cavitation events have also been found to drive chemical reactions in a manner similar to that of ultrasonic sonochemistry, efficiently decomposing and destroying contaminating organic compounds. The reactions have been found to proceed more rapidly in the presence of air injection or oxygenation by this means.

This work was done by Georges L. Chahine of Dynaflow, Inc. for Johnson Space Center. MSC-24019-1

NASA Tech Briefs Magazine

This article first appeared in the June, 2012 issue of NASA Tech Briefs Magazine.

Read more articles from this issue here.

Read more articles from the archives here.