Performance of low-cost ejectors

Abstract

Despite its widespread use in agricultural systems, the Venturi-type ejector presents lower efficiency than that obtained by conventional jet pumps. In this study, low-cost ejectors built from PVC T-junctions, with geometry similar to that of the conventional jet pumps, were developed and evaluated experimentally. The tests were carried out on ejectors with nominal diameters of 25 and 32 mm with area ratios of 0.25, 0.35, and 0.53. For each diameter, a Venturi-type ejector with an area ratio of 0.35 was also employed. The ejectors developed in this research presented efficiency between double and triple of that of the Venturi type, with a maximum of 30.5% being reached with the ejector of 25 mm and area ratio of 0.35. The head-loss coefficients for each component of the ejectors were evaluated by fitting a one-dimensional model. The results showed that the low-cost ejectors developed here presented an operation comparable to that of conventional jet pumps and had a better benefit/cost ratio than the Venturi-type ejectors.