## 1 Introduction  
Liquid-gas ejectors, in which the secondary fluid is gas, have the potential to be used in carbon capture and storage. Ejectors are used to draw more fluid from wells in the oil and gas sector, helping to increase output and reduce costs. Ejectors are also used for post-combustion carbon capture in power plants, to improve external waste heat to reduce the quantity of turbine steam needed for solvent regeneration. In addition to gas compression, ejectors may also be used for refrigeration and CO\({}_{2}\) transportation and storage, and numerous studies have been done to analyze and improve their effectiveness [1]. One of the challenging issues that has always attracted the attention of the experts is how to control and reduce greenhouse gas emissions because of their vast negative environmental impacts [2]. Furthermore, due to the district regulations related to greenhouse gas emissions, experts and scholars have recently focused on the more efficient and clear processes in which the amount and type of the released gas are under control [3]. Due to the demand for hydrocarbon-based fuels, the oil and gas sectors play a pivotal role in the current situation. During the extraction process of gas and oil, some co-products are created that must be discharged into the surrounding environment. Burning the mentioned gaseous material in flare systems is a common method that is followed in gas and oil fields. Although burning the hazardous gaseous products in the flare systems boosts the safety of gas and oil fields and diminishes the internal pressure of the extraction systems, it has a catastrophic impact on the surrounding environment [4]. From economic and environmental standpoints, utilizing flare gas recovery units in the gas and oil fields has many merits, such as boosting production efficiency, decreasing operating costs and maintenance, and reducing noise and flare emissions [5]. In the chemical-based processes that experts face with coaxial flow systems, ejectors are considered as one of the most critical elements in which a high-pressure current entrains a low-pressure current. This element is widely utilized in flare gas recovery units. To delve deeper into the role of the flare gas recovery unit, it should be highlighted that the recovery unit collects gases before entering to flare unit, and compressing and cooling them remarkably reduces the amount of discharged gas to the environment. The recovered gas extracted from the flare gas recovery unit is utilized as feed in other sections of the chemical plant. The common form of a flare gas recovery unit with a liquid-based ejector and a liquid-gas ejector's geometry has been depicted in Figure 1. The general ejector includes, as shown in this Figure, a nozzle (1), a suction chamber/converging part (2), where one phase is injected into the system at a high rate of speed via a nozzle, and a low-pressure zone is created in accordance with [PERSON]'s principle, a throat (3), where the gas and liquid phases mix and a dispersion of gas and liquid is formed, a pressure recovery part (4), and a contactor (5) for providing gas-liquid contact. Because the ejector is so crucial in the flare gas recovery unit, a lot of research has been done on it in both theoretical and experimental ways. In this regard, computational fluid dynamics is applied to evaluate the performance of ejectors in different conditions and different fluids [6; 7; 8]. For instance, [PERSON] et al. [9] provided a review paper about the most recent innovations, advances, and novel applications of single-phase ejectors. A wide range of aspects of mentioned ejector were scrutinized. Moreover, the potential of the single-phase ejector to employ as a single equipment or integrate with other elements in a combined system was assessed. Two-phase ejectors are another type of ejector in  
Figure 1: (**a**) The schematic of a flare gas recovery system, (**b**) the typical geometry of a liquid jet ejector. which two different materials flow inside the ejector.