Active vapor transfer and condensation in eductor for fresh-water production.

Eductor is a static mechanical device converting primary flow pressure energy to velocity energy, creating low-pressure zone for suction of secondary fluid. The primary fluid is water at low temperature and secondary fluid is saturated water vapor, the vapor gets entrained in the primary fluid and is condensed. This study is focused on developing eductor as an active vapor transfer and condensation unit. It simplifies and significantly reduces the footprint of existing off grid thermal desalination unit by replacing large condensers and vacuum pumps. The study on performance of eductor, its applicability and design optimization has been discussed as a part of this work. The methodology involves experiments, computational analysis and analytical study. The momentum transfer during degassing process, results into vacuum generation. Both the momentum and mass transfer contribute to entrainment of secondary fluid. The installation of eductor to permeate chamber in a Membrane distillation (MD) unit, exacts the permeate flux to the eductor for direct contact condensation and cooling. The existing design of eductors are not focused to this intended purpose; hence design was optimized by increasing the interphase interaction area. [ABSTRACT FROM AUTHOR]