Numerical Study of the Effect of Geometric Parameters on the Performance of Solid-Liquid Ejectors

The present research numerically studies the effect of geometric parameters on the performance of two-phase solid-liquid ejectors. The equations governing the flow inside the ejector include continuity and momentum equations from an Eulerian perspective using the control volume method. The geometric parameters under study were the convergence angle, divergence angle, area ratio (nozzle to the throat), and nozzle position (distance between the nozzle outlet and the start of the throat) in the ejector. In this study, significant design parameters, including the entrainment ratio, critical pressure, and ejector efficiency were introduced and calculated for all the geometric parameters. The homogeneous and the two-phase mixture models were employed to simulate the secondary flow. The results indicate that the data from the two models were in good agreement at low volume fractions (5%), such that the largest error occurred at an area ratio of 0.26 and was equal to 2.3%. The results also indicate that the ejector efficiency increases with an increase in the convergence angle up to 20°, after which it decreases. Moreover, an increase in the area ratio up to 0.22 improves the efficiency of the ejector, after which this efficiency is reduced. Decreasing the divergence angle and increasing the nozzle-to-throat distance also enhance the ejector efficiency. In addition, optimal values were obtained for the design parameters by varying the geometric parameters. These values can be employed according to the application for which the ejector is being used.