Effect of Geometry on Mass Transfer Characteristics of Ejectors

Abstract

Ejectors are gas-liquid contactors that are reported to provide higher mass transfer rates than conventional contactors. Detailed experiments were performed, and Computational Fluid Dynamics (CFD) modeling studies were undertaken to understand the mass transfer characteristics of the ejector geometry. The mass transfer coefficient and interfacial area were predicted from the volume averaged energy dissipation rate. Studies show that there is an optimum ratio of nozzle area to throat area (area ratio), at which the liquid entrainment rate is the highest. Using optimized geometry can lead to substantial economic benefit in the industrial practice.

Numerical Simulation of Bubble Coalescence and Break-Up in Multinozzle Jet Ejector

“…The numbers of researchers have attempted to optimize performance of jet ejector [40,51,[54][55][56][57][58][59][60][61][62][63][64][65][66][67][68][69][70][71] due to its increasing growth rate in usage. Many researchers have studied the mass transfer characteristics and performance of the jet ejectors followed by contactors, draft tube, packed column, or bubble column and they have similar conclusion that there is less mass transfer coefficient in the extended portion in comparison to the ejector [31,34,39,56,[69][70][71][72][73][74][75][76][77][78][79][80][81][82][83][84][85][86][87]. Dutta et al [74] and Gamisans et al [60] studied the jet ejectors and observe that jet ejector without diffuser or throat is less effective in comparison to ejector with them.…”

Flow and Oxygen-Transfer Characteristics in an Aeration System Using an Annular Nozzle Ejector

“…7 The effects of different operating conditions such as nozzle velocity, pressure drop, and ejector geometry parameters on the performance of ejectors have been experimentally investigated by several researchers. 8−14 Mass-transfer and hydrodynamic characteristics of ejectors using air or water as the primary fluid or the entrained fluid have been investigated by Balamurugan et al, 15 Kim et al, 16 Mandal et al, 17 Cramers and Beenackers, 18 and Havelka et al 19 An ejector works like a vacuum pump without usage of piston, rotor, or any other moving components. In general, the ejector is a less efficient device, because most of the fluid machineries are operated by the normal stresses on the rotating blades, while the ejector is driven only by a pure shear action between the primary and the secondary streams.…”

“…Ejectors are being used as gas–liquid dispersion devices for many purposes in many industries, since they have high mass-transfer and mixing rates. , Many reports have researched the gas–liquid flow and mixing in ejectors, but the results are different and have individual scope of application due to the different ejector geometries, study methods, and species of fluids . The effects of different operating conditions such as nozzle velocity, pressure drop, and ejector geometry parameters on the performance of ejectors have been experimentally investigated by several researchers. − Mass-transfer and hydrodynamic characteristics of ejectors using air or water as the primary fluid or the entrained fluid have been investigated by Balamurugan et al, Kim et al, Mandal et al, Cramers and Beenackers, and Havelka et al…”

“…There are two configurations of ejectors as shown in Figure . The first is the conventional central-driven ejector, in which the primary fluid passes through the inner nozzle inside the ejector and the suction fluid passes through the annular periphery surrounding the nozzle. − Lima Neto et al and Baylar and Ozkan investigated the behavior of horizontal gas–liquid injection using a venture nozzle in a water tank as this study. Gas–liquid mass transfer in a pumped circulation loop reactor using a venture-type sparger was investigated by Fadavi and Chisti .…”

Oxygen Transfer Characteristics of an Ejector Aeration System

“…This creates a vacuum in a secondary inlet, pulling secondary fluid into combination with the primary flow [8,9]. Mass transfer and hydrodynamic characteristics of ejectors using air or water as the motive fluid or the entrained fluid have been investigated experimentally and numerically by Balamurugan et al [10,11], Kim et al [12] and Utomo et al [13]. The effects of different operating conditions such as nozzle velocity, pressure drop, and ejector geometry parameters on the performance of ejectors have been experimentally investigated by several researchers [7,[14][15][16][17][18].…”