## 1 Introduction
The simulation of these types of ejectors was precisely reviewed by [PERSON] et al. [10]. [PERSON] et al. investigated the experimental and computational fluid dynamics of an ejector with a new geometry to improve its performance. The multi-nozzle and swirls effect features are combined in the proposed inlet geometry. With the applied changes, the ejector efficiency increased by 158% [11]. [PERSON] et al. [12] tested the configuration of gas-gas ejectors based on numerical analysis. They considered different operation circumstances and geometries, and a CFD model was developed to assess the proposed system. The results demonstrated that the system's performance is influenced by the current and character of the ejector. In another study [13], an innovative liquid-liquid ejector was hydrodynamically evaluated by CFD. The results of validation demonstrated that the simulation's findings had enough accuracy. Moreover, some critical variables, such as jet velocity, column to nozzle diameter ratio, and two phases flow ratio, were selected, and their impacts on the proposed system's efficiency were assessed. [PERSON] et al. [14] conducted a numerical modeling of a multi-nozzle jet ejector using CFD. They evaluated three different sets of nozzles inside a jet ejector and compared the finding results. Additionally, they assessed the dynamic of break-up and bubble coalescence in the mentioned system by considering 3D numerical domains. Void fraction, velocity, and bubble size were three critical parameters tested in a dual-channel optical fiber probe in a liquid-gas annular ejector system by [PERSON] et al. [15]. Based on the results and comparing them with experimental data, the accuracy of measured parameters was verified. A single phase model based on CFD was developed by [PERSON] et al. [16]. The authors simulated a gas-liquid nozzle to anticipate the gas induction rates. Additionally, the influences of variables such as the nozzle's mixing length, the diameter of the nozzle, suction chamber geometry, etc., were scrutinized and reported. Operating circumstances are another critical parameter that was especially evaluated by [PERSON] et al. [17]. To this end, a two-phase CFD-based model was developed for an ejector. In that investigation, Liquefied natural gas (LNG) and Boiling Off Gas (BOG) were chosen as primary and secondary fluids inside the simulated ejector. The simulation's results revealed that the phase change had a remarkable impact on the system's efficiency. The fluid type inside the liquid jet ejector was another parameter tested by [PERSON] et al. [18]. Unlike other investigations in which the impacts of the turbulent phenomenon have been neglected, in that research, authors tried to evaluate the turbulence phenomena and its influences on the issues such as jet dynamic and rate of gas induction. They reported that the mentioned issue should be considered to reach a reliable and more correct CFD model. The mixing flow behavior and its impact on liquid-gas ejectors were modeled by [PERSON] et al. [8]. The model was developed based on the realizable k-\(\varepsilon\) turbulence mode by ANSYS-FLUENT software. By simulating the system, all critical variables were investigated for the ejector. A great number of scholars and experts have been widely working on both the computational evaluations and experimental-based investigations around ejectors and their characteristics [19; 20; 21; 22]. To the best of our knowledge, there has been no hydrodynamic study of carbon dioxide capture in an ejector in the literature prior to this study. The present work firstly evaluates the hydrodynamics of a 3D liquid-gas (water-air) ejector. In this study, the experimental values such as water flow rate and separator pressure are used from the experimental work by [PERSON] [23]. The impacts of motive liquid flowrate and outlet pressure on the air entrainment rate and air hold-up were assessed using 3D CFD simulation.