# Development of Hybrid Airlift-Jet Pump with Its Performance Analysis
## 1 Introduction  
A pump is a device that actuates liquids by mechanical actions. Numerous types of pumps exist according to methods used to actuate the fluid. Both the airlift and jet pumps can be classified into indirect types, where the direct contact of mechanical parts is not required to drive the fluid. Airlift pumps operate on the air and are inserted into vertical pipes, which lowers the density of the fluid mixture and lifts it. Jet pumps (or educator-jet pumps) use a jet, often of steam, to create a low pressure. This lower pressure draws in the target fluid and propels it into a higher-pressure region. The primary merit of these types of pumps is their simple operating mechanism due to their simple structure, and they can operate on ill-conditioned target liquids and are thus durable. However, the demerit of these pumps is their low efficiency. Therefore, our aim is to develop a new pump concept by combiningthe operating mechanisms of the airlift and jet pumps, which supplements their weakness of low efficiency, and reinforces their advantages simultaneously. The operating mechanism of a jet pump is based on the principle of kinetic energy exchange of a primary fluid with a secondary fluid in a mixture chamber, as well as drawing the secondary fluid by the static pressure difference. Jet pumps can be characterized according to the types of primary and secondary fluids as gas-gas, gas-liquid, and liquid-liquid. It has been more than a century since the basic design of a jet pump was first introduced [1]. Initially, one-dimensional methods were used to predict the pump performance [2; 3; 4]. Although these studies facilitated the basic understanding of the simple operating mechanism of a jet pump, they could not investigate the local flow phenomenon that generally strongly depends on three-dimensional flow characteristics. Therefore, studies using computational fluid dynamics (CFD) [5; 6; 7; 8; 9; 10; 11] and experimental [12; 13; 14; 15; 16] methods were performed. To obtain more reliable and accurate designs of jet pumps in different applications, CFD techniques are widely used owing to its reasonable cost. Some studies have focused on the performance of ejectors for various types of refrigerants used in heat pumps [5] and eject refrigeration systems [6]. [PERSON] [7] investigated the influence of the primary nozzle exit position and the mixing section converging angle on the ejectors' performance. [PERSON] [8] investigated gas-liquid ejectors by varying the geometry, fluid property, and operating condition, and compared them with a single-phase ejector. [PERSON] [9] performed a global optimization to improve the jet pump efficiency. [PERSON] et al. [10; 11] investigated the characteristics of the steam jet pump using saturated steam and the direct-contact condensation model. Additionally, studies using experimental and numerical approaches have been performed. [PERSON] et al. [12; 13] performed visualization experiments and developed a two-phase flow model for the performance prediction of the next-generation nuclear reactors. [PERSON] et al. [14] compared six different turbulence models and proposed the Shear-Stress Transport (SST) k-\(\upsilon\) model as the most appropriate one for the numerical method to investigate supersonic ejectors. [PERSON] et al. [15] performed experimental studies to measure the performance of vapor-water ejectors in different temperature conditions. [PERSON] et al. [16] performed the optimization of the ejector shape using analytical and experimental approaches. The operating principle of the airlift pump is relatively simple compared to that of the jet pump. It is a type of device that raises liquids or mixtures of liquids and solids through a vertical pipe, partially submerged in the liquid, using the compressed air introduced into the pipe near the lower end [17]. Many studies have been performed to investigate the factors that affect the performance of airlift pumps.