Performance Study of Eductor with Finite Secondary Source for Membrane Distillation

Abstract

This is an experimental work performed to identify the influence of direct contact condensation inside an eductor. The fluid used in the experiments is water in two different phases: liquid and vapor, for primary and secondary flows, respectively. This study was conducted in an attempt to establish the suitability of an eductor as a combined vacuum generator and condenser for membrane desalination applications. The pressure and temperature measurements at critical points in the flow paths have been summarized to identify the influence of primary flow on secondary fluid saturation and condensation. In addition, the mechanism of phase change has been explained through the photography of fluid flow in a two-dimensional eductor. A consistent oscillation of the gas-liquid interface was observed during steady-state operations of the eductor. This work also contributes to the validation of future computational research. It will provide a baseline for computational thermal fluid analysis related to the mixing of condensing and non-condensing flow. In general, the research encompasses the practical operational scenario and provides information on the heat and mass transfer of direct contact condensation with a finite secondary source.

Design Enhancement of Eductor for Active Vapor Transport and Condensation during Two-Phase Single-Species Flow

“…Koirala et al [19] studied the comparative performance of an eductor in entraining condensing and non-condensing flow with otherwise equal properties. This was part of series of publications in developing an eductor as an effective alternative for active vapor transfer and condensation in the desalination process [20,21]. The entrainment ratio was much higher in the case of condensing flow compared to non-condensing flow.…”