Ejector Performance Research Articles

Performance improvement of CO2 two-phase ejector by combining CFD modeling, artificial neural network and genetic algorithm

The ejector, as one of the core components of the CO2 trans-critical ejection refrigeration system, plays an important role in improving refrigeration capacity and reducing compressor power consumption. Although the ejector can be optimized by experiment and Computational Fluid Dynamics (CFD) simulation to improve its performance, these methods are time-consuming and complicated. This study aims to propose a method to improve the performance of the CO2 trans-critical two-phase ejector assisted by using CFD, artificial neural network (ANN), and genetic algorithm (GA). Firstly, the influence of geometric parameters on ejector efficiency was analyzed by using CFD technology, and the database was generated. Next, the complex and time-consuming CFD model was replaced by the ANN surrogate model established to predict the ejector performance. Finally, the GA method was used to optimize the ejector to maximize the ejector efficiency. The results show that the efficiency of the optimized ejector is 35.39%. The optimized ejector increases the secondary flow velocity and eliminates the vortex in ejector, and the efficiency of the optimized ejector is raised by more than 8% on average than that of initial ejector under different primary and secondary flow conditions. The research shows that the combination of CFD, ANN, and GA has higher reliability and better performance in the optimization design of CO2 two-phase ejector.

Thermodynamic investigation on low GWP drop‐in alternatives to HFC‐245fa in ejector refrigeration cycle for air condition application

AbstractThe ejector refrigeration cycle (ERC) with HFC‐245fa can achieve high efficiency and reliability for air conditioning applications. However, because of its high global warming potential (GWP), HFC‐245fa needed to be phased out according to recent relative regulations. In this study, four promising alternatives to HFC‐245fa were investigated and evaluated, including HC‐600, HCFO‐1233zd(E), HFO‐1336mzz(Z), and HCFO‐1224 yd(Z). Besides their low GWP, these alternatives also have similar vapor pressure curves to HFC‐245fa, which represents a possibility for refrigerant drop‐in replacement in ERC. Thermodynamic real gas modeling of the ERC was adopted in this study for more accurate results, and a critical performance evaluation and comparison with those candidates in ERC were carried out. The results indicate that HCFO‐1233zd(E) and HCFO‐1224 yd(Z) are outstanding candidates for ERC according to the higher coefficient of performance, entrainment ratio, exergy efficiency, and lower pump power consumption, and the COP relative differences of these two refrigerants would reach 5.5% and 4.6%. HFO‐1336mzz(Z) consumes 33% less power at the pump than HFC‐245fa under the same conditions and refrigeration capacity. Minimal pump power consumption is its advantage. Although HC‐600 is prominent, with the largest coefficient of performance and entrainment ratio, its flammability is not conducive to its popularization. Machine learning is available to predict the performance of ejectors employing different refrigerants. This paper helps to properly select refrigerants for ERC and to pre‐evaluate the refrigerants' application under different working conditions.

Experimental investigation of a novel variable geometry radial ejector

This work focuses on improving ejector performance in variable conditions by developing a radial flow variable geometry radial ejector (VGRE). The research objective was to demonstrate the performance of the improved VGRE, which can operate more effectively under changing operating conditions compared to a fixed geometry design. The improved VGRE was developed and experimentally tested to enable adjustment of the nozzle and ejector throat areas to suit different ejector operating conditions in various applications. Radial ejectors have a smaller size than axial ejectors, which is a significant advantage in some applications. Results showed that the improved VGRE achieved higher entrainment ratio and critical compression ratio compared to a fixed geometry design and that optimal performance was obtained with nozzle and duct throat separations of 0.5 mm and 3.0 mm, respectively. The results also indicated that the wall static pressure in the throat region of the improved VGRE was similar to that observed in conventional axial ejectors and showed an average improvement of 107 % in entrainment ratio and 76 % in critical compression ratio relative to previous studies of air ejectors. The findings suggest that the improved VGRE concept could be applied to a wide range of applications in the future.

Experimental and numerical study on the ejector containing condensable species in the secondary flow for PEM fuel cell applications

Phase transitions in two-phase ejectors have gained attention in various applications, including refrigeration, desalination, and fuel cell systems. The phase transition of condensable components in the primary flow significantly affects the ejector performance. However, studies on the phase transition of condensable species in the secondary flow are scarce. Consequently, this study aims to investigate two-phase flow characteristics of the ejector containing condensable species in the secondary flow. A schlieren experimental system with a visual rectangular ejector was constructed, and a transient Eulerian-Lagrangian two-phase flow model incorporating non-equilibrium condensation was developed. The numerical simulations achieved an average deviation of 4.7% in the entrainment ratio compared to experimental measurements, with a maximum deviation of 11.6%. The schlieren experiment revealed that the condensable species in the secondary flow can condense when the primary pressure exceeds 0.30 MPa. The numerical results showed that the condensed droplets reach a minimum proximity of approximately 3 mm from the primary nozzle exit and exhibit a divergence angle ranging from 7° to 12° as they traverse with the gas flow. Additionally, increasing the primary flow pressure from 0.2 MPa to 0.5 MPa resulted in a noticeable lengthening of the first shock wave, from 1.45 mm to 3.00 mm.

Numerical Analysis of Steam Ejector Performance with Non-Equilibrium Condensation for Refrigeration Applications

In recent years, there has been great interest in developing cooling systems with humidity- and temperature-independent control capabilities that can operate efficiently at varying temperatures. This paper proposes a bi-loop double-evaporator ejection–compression cycle, which utilizes low-grade heat and is suitable for the construction industry. The proposed cycle involves the concurrent operation of a vapor compression cycle and an ejector refrigeration cycle that enables it to handle altered pressure levels and operate with varying compression ratios all the way to a common condenser pressure. Conventional computational fluid dynamics (CFD) approaches often model steam as an ideal gas with single-phase flow. In contrast, this research employs the wet steam model to optimize ejector geometry. The wet steam model takes into account non-equilibrium water vapor condensation, thus providing a more precise assessment of spontaneous condensation behavior and its impact on ejector performance. When compared to the conventional dry gas model, the use of the wet steam model dramatically decreases the entrainment ratio error from 16.24% for single-phase steam to 3.92% when compared to experimental data. This study concentrates on four critical attributes of wet steam, including Mach number, droplet nucleation rate, average droplet radius, and liquid mass fraction, to develop a strategy for enhancing ejector performance and efficiency. The study demonstrates that optimal area and primary nozzle diameter ratios for the steam ejector are 5 and 2.4, respectively. Increasing the area ratio mitigates condensation intensity, thereby reducing the liquid mass fraction in the diffuser. Overall, this paper provides valuable insights into improving and optimizing ejector performance, thus highlighting the importance of considering the behavior of spontaneous condensation in ejector design and modeling.

Numerical and Experimental Investigation of Supersonic Binary Fluid Ejector Performance

Ejectors are simple mechanical devices with no moving parts which convert the pressure energy of a motive fluid to kinetic energy and generate suction of the secondary fluid. The ability to recover waste heat, to operate using solar power and the ability to use geothermal energy make ejector-based systems attractive in different industrial applications. The main challenge of ejector-based refrigeration systems is their relatively low coefficient of performance (COP). In order to increase the ejector performance, two chemically distinct fluids can be used in the refrigeration cycle. It is suggested that a higher molecular mass be used for the motive fluid to improve the entrainment ratio of the binary fluid ejector (BFE) and thus the system COP. Inert gas combinations of argon–helium and krypton–air are studied in this paper using computational fluid dynamics (CFDs) and experimental measurements. All CFD cases were axisymmetric and the appropriate turbulence model was selected based on experimental validation. Specifically, the entrainment ratio and the static pressure along the ejector wall were measured to validate the CFD predictions. It was found that the molar entrainment ratio was significantly higher in argon–helium compared to krypton–air. The static pressure measurements along the wall, in addition, exhibited good agreement with the results obtained via computational fluid dynamics (CFDs).

Fuel ejector design and optimization for solid oxide fuel cells using response surface methodology and multi-objective genetic algorithm

Ejectors are the main devices used to circulate high-temperature anode exhaust gases for solid oxide fuel cells (SOFCs) for recovering and utilizing water vapor and heat. To optimize the performance of a high-temperature fuel ejector for SOFCs, we established a numerical model of the ejector and then validated it using the experimentally obtained primary flow and secondary flow mass flow rates. The influence of the primary nozzle exit position (NXP), length (Lm) and radius (Rm) of the mixing chamber, and other key structures, on ejector performance was examined via Response Surface Methodology (RSM). The performance of the ejector gradually decreased with increasing NXP and Lm and first increased and then decreased with increases in Rm. The sensitivity of the ejector performance to Rm, Lm, and NXP decreased sequentially, and its structure was optimized using a multi-objective genetic algorithm. The entrainment ratio of the optimized ejector reached 6.66, representing an increase of 23.37 % compared with the original ejector. This work proposes a design and optimization method for optimizing the ejector to meet the high entrainment ratio required by SOFCs. The response surface methodology was used to realize the research on the influence of multi-structural parameter coupling on the performance of the ejector, which significantly improved the optimization efficiency and accuracy. This study also introduced multi-objective genetic algorithm on the basis of response surface methodology to optimize the performance of the ejector. Through continuous gene mutation and iteration, the ejector has the best performance. This provides a new direction for future SOFC fuel ejector performance optimization, that is, introducing various optimization algorithms on the basis of multi-parameter coupling effects, and finally solving an optimal performance through continuous permutation, combination and iterative calculation.

Use of a New Gas Ejector for a TEG/TREG Natural Gas Dehydration System

Glycol dehydration is the most common and economical water removal method from natural gas streams. However, dehydration of low-pressure natural gas requires the use of higher concentration TEG (Triethylene Glycol) or TREG (Tetraethylene Glycol). This article describes how the ejector can be used to create a vacuum in the glycol reboiler to achieve a higher concentration of L-TEG/L-TREG (Lean Triethylene Glycol/Lean Tetraethylene Glycol). Process simulations of the gas dehydration and glycol regeneration units were carried out in Chemcad software. Simulations were performed for decreasing values of gas working pressure and TEG/TREG regeneration pressures. Dehydration unit efficiency was tested for two values of glycol flow rates. Ejector performance simulations were executed for two positions in the process flow line. The influence of pressure reduction in the glycol reboiler on the concentration of L-TEG/L-TREG and the water dewpoint of natural gas has to be found significant. The increase in glycol flow rate has a greater impact on TREG than for TEG. Creating a vacuum with an ejector in a TEG/TREG reboiler has been shown to be an attractive way to improve the efficiency of natural gas dehydration. The position of the ejector at the end of the vapor flow line, downstream to the condensed water separator, allows for a significant reduction in motive gas consumption.

Experimental and numerical study on low-temperature supersonic ejector

Ejectors have emerged as a viable solution for handling Boil-Off-Gas (BOG) generated by cryogenic storage tanks. The efficiency of ejector-based systems plays is highly dependent on the ejector's performance which is influenced by various factors including the geometry of the ejector and the boundary conditions. In this study, an axisymmetric supersonic ejector was designed, optimized, and evaluated for BOG removal. The baseline geometric dimensions design of the ejector was obtained via theoretical analysis. Subsequently, computational fluid dynamics (CFD) simulations were employed to optimize the boundary conditions and geometrical parameters. Experimental investigations were conducted to validate the design and evaluate the ejector's performance. The results highlighted the significant influence of two key parameters, namely, the mixing chamber diameter (Dm) and the nozzle exit position (NXP), on the ejector's performance. Optimized Dm showed an increase of about 12.5% compared with the baseline geometry. By operating the ejector within its on-design geometric and boundary conditions, the maximum entrainment ratio (ER) was achieved. The CFD models successfully identified and validated various flow phenomena, including double choke, single choke, and backflow, which were consistent with the experimental observations. Both the numerical models and experimental findings demonstrated that the modified ejector achieved an entrainment ratio of 1.06 under its design condition showing a 33.66% increase compared with that obtained using the baseline geometry. These results indicate the potential of the supersonic ejector as an alternative solution for BOG applications, emphasizing its efficacy in handling this industrial challenge.

The performance analysis of a variable geometry ejector utilizing CFD and artificial neural network

Currently, ejector-based refrigeration applications are attracting much attention as ways of improving refrigeration systems and energy conversion applications. The ejector performance is influenced mainly by the operating conditions and the geometry of the system, so the geometry parameters need to be optimized for optimal performance. However, due to the fluctuating operating conditions no fixed geometry will satisfy the whole range of performance requirements. Thus, a dynamic geometrical ejector is more feasible. A CFD model designed to test the functionality of a Variable Geometry Ejector with a movable spindle and variable nozzle exit position is presented, utilizing R1234yf due to its environmental advantages. In instances where the primary temperature falls below the ideal threshold, the optimal outcome was achieved by positioning the nozzle exit at 0 mm. In contrast, if the primary temperature is equal to or exceeds the optimal level, a negative value of the nozzle exit position can enhance the entrainment ratio, raising the critical temperatures by up to 11.8%. Not utilizing a spindle resulted in a higher entrainment ratio, but it also yielded the smallest stable operating range among the spindle-equipped scenarios. Further, adopting a spindle with a nozzle position of 0 mm led to a significant improvement in critical temperature, increasing it by 25.8%. A Design of Experiment analysis is conducted to show the most influential factors on the primary, and secondary mass flow rates and the entrainment ratio. An artificial neural network that merges the operating conditions and geometrical parameters succeeds in predicting the ejector entrainment ratio with R2 = 99.81%.

Performance and mixing process investigation of a novel mixing-enhanced ejector

Ejector refrigeration systems rarely require electrical energy, satisfying the requirements of sustainable development and low carbon emissions. However, owing to the limitations of the operating conditions, the ejector performance is not sufficient, and there is an urgent need to improve the entrainment performance of the ejector. In this study, experiments and numerical simulations were performed on a conventional ejector, and the numerical simulation results were fitted with the experimental data. A numerical simulation was used to investigate the mixing process and entrainment performance of the novel mixing-enhanced supersonic steam ejector. The optimal values of lm = 120 mm and dc = 57.5 mm achieved the best entrainment ratio (0.778) for the novel ejector under 5%-tab blockage ratio. The results showed that the entrainment performance of the novel ejector improved by 51.1–54.7% and 10.5–12.3% compared to those of the conventional ejector and the conventional ejector with an adjusted mixing chamber, respectively. This was because the generated streamwise vortices entrained more secondary flow into the mixing chamber, and the mixing process between the primary and secondary flow avoided unnecessary kinetic energy loss, increasing the mixing efficiency and accelerating the secondary flow crashing out of the diffuser.

Transient numerical study of CO2 two-phase flow in a needle adjustable ejector

Steady-state numerical modeling is mostly used for predicting the flow and transport characteristics in an ejector, but it may not be able to reflect the actual performances of an ejector when operating condition varies. Moreover effects of needle movement on the performances of an ejector is not very clear. In this study, a transient heterogeneous mixture model was developed for a two-phase CO2 needle adjustable ejector with motive nozzle inlet in supercritical, critical or sub-critical regions. The dynamic mesh method was used to control the needle movement, and the unsteady coupling solution between the needle movement and the flow field is solved for the adjustable two-phase CO2 ejector. Modeling results show that the transient modeling can predict dynamic performances of CO2 ejector more accurately than the steady-state modeling. Based on the transient modeling, it is found that as the needle moves further into the motive nozzle throat, effective nozzle throat area decreases, expansion angle of motive flow increases then decreases, the velocity at the motive nozzle outlet decreases then increases, and entrainment ratio decreases, then increases sharply, then decreases, finally become negative. High pressure at the motive nozzle inlet leads to high entrainment ratio owning to high velocity at the motive nozzle throat outlet. A sudden increase of pressure at the motive nozzle inlet in different thermodynamic state regions (supercritical, sub-critical) leads to different dynamic performance responses and oscillation times of ejector. The mechanisms of boundary layer separation and backflow vortices as well as shock waves were explored to explain the suction flow chocking phenomena. This study is helpful to understand flow mechanisms inside the CO2 ejector, and improve optimal design and control of an adjustable two-phase CO2 ejector in variable operating conditions in practice.

Investigation on improvement potential of steam ejector performance in refrigeration cycle via constant rate of momentum change design method

In this paper, an ejector created by the constant rate of the momentum change method (CRMC ejector) was experimentally studied and compared with the widely used constant pressure method (CPM ejector) under the same ejector area ratio. The influence of the boiler temperature, evaporator temperature, and primary nozzle size on the ability to improve the performance of the CRMC ejector was examined. The results indicated that at the same ejector area ratio, the CRMC ejector always performed a higher mass entrainment ratio than the CPM ejector. However, the critical condenser pressure was similar. The average percent improvement of the entrainment ratio via the CRMC ejector was approximately 20%. Based on the photograph taken from the transparent ejector, a compression shock wave was still found in the flow process of the CRMC ejector. This shows that an improvement potential of the CRMC ejector does not concern the compression shock wave as proposed in the design theory. The key to improvement was believed to be its ability to mitigate the momentum loss during the mixing process. In such a case, some simulation works based on computational fluid dynamics (CFD) were employed for explanation. This can also confirm that the compression shock wave via CRMC ejector is still found. In addition, this paper compared the experimental results with the theoretical results obtained from 1-D theory and CRMC theory to alternatively discuss that an improvement potential of the CRMC ejector was mainly the cause of a lower mixing loss.

Working mechanism and characteristics analysis of a novel configuration of a supersonic ejector

The growing awareness of utilizing low-grade energy has encouraged the scientific community to conduct research on supersonic ejectors. Most previous studies have investigated on the geometry parameters or profiles of supersonic ejectors, but few studies have focused on improving the ejector configuration. This paper presents a novel configuration of a supersonic ejector which has the advantage of better performance than the conventional ejector in double-choking mode. First, the novel configuration and its working mechanism are presented, and the entropy generation of the primary fluid is compared theoretically between the novel and conventional configurations. Second, validation of the novel configuration mechanism is performed using CFD. The velocity and pressure distribution, performance characteristics, and entropy generation at different outlet pressures are presented and analyzed in comparison to the conventional ejector. The normal shock intensity in the novel configuration is reduced and the total entropy generation decreased, thereby improving the ejector's performance. Finally, the impact of the geometric parameters of the novel configuration is evaluated, pointing out its limits and the need of further investigation and experimental studies for optimal design.

A theoretical model for performance evaluation of a novel configuration of supersonic ejectors

Few researches have investigated on the improvement of supersonic ejector configuration. This paper presents a theoretical model for evaluating the performance of a novel supersonic ejector configuration that has not been investigated before. Under various geometry parameters and operating conditions, the working performance of ejectors in conventional and novel configurations is investigated. In addition, the performance characteristics of the novel configuration were analyzed, and the Kantrowitz limit was introduced to obtain a reference value for the compression surface radius on a theoretical basis. 24 ejectors with different geometry parameters, including the conventional and novel ejectors, are designed and tested using CFD approach. The results show that the performance of the novel ejectors is better than that of the conventional ejectors within the deterioration point, and the trend of their critical outlet pressure is consistent with the theoretical model. Moreover, the deterioration point is well predicted, and the performance of the novel configuration decreases when the compression surface radius exceeds the deterioration point. Last, the relationship between the flow field and key parameters of the novel configuration was illustrated by analyzing the Mach number contours and pressure distribution of the conventional and novel ejectors.

Advanced exergy analysis of a solar-driven cascade ejector system with heat storage

Solar-driven cascade ejector system can not only promote the utilization reliability of the solar energy, but also improve the performance of solar energy systems. This paper proposes a novel solar-driven cascade ejector system which integrates a solar ejector heat storage subsystem with R290 as refrigerant and a transcritical CO2 ejector-expansion refrigeration subsystem. The conventional and advanced exergy analysis methods are utilized to investigate the system’s exergetic performance, and explore the interactions among the system components and their improvement potential. The effects of compressor efficiency, area ratio and efficiency of ejectors on the exergetic performance of system and components are investigated. The analysis results show that the transcritical CO2 ejector-expansion refrigeration subsystem has higher exergy efficiency and its components have small exogenous exergy destruction. The endogenous exergy destruction and the avoided exergy destruction of cascade system account for 88.85% and 41.46%, respectively. Besides, 66.35% of exogenous exergy destruction of middle heat exchanger is caused by the compressor and CO2 ejector, and to improve the performance of CO2 ejector and CO2 evaporator would decrease the exergy destruction of compressor. CO2 ejector and R290 ejector have the superior improvement potential in each subsystem compared to other components. The rise of ejector area ratio would increase the endogenous exergy destruction of ejector. For the system with high-performance compressor, R290 ejector efficiency should be attracted more attention to reduce its avoided endogenous exergy destruction.

Design, fabrication, and investigations of prototype supersonic micro-ejector for innovative cooling system of electronic components

Innovative approach for electronics cooling was proposed, i.e. heat generated by a part of electronic equipment, e.g. CPU, is absorbed by heat driven micro-ejector refrigeration system that can provide cooling of other electronic components, e.g. GPU. It was demonstrated the procedure of design, fabrication, and experimentation on the supersonic micro-ejectors for the case of isobutane as a working fluid for such system. It was demonstrated that it possible to design and fabricate the micro-ejector of cooling capacity in the range 3 W suitable for cooling of electronic equipment. For the discussed micro-ejector entrainment ratio obtained was app. 0.20 under conditions of the motive heat source temperature app. 60 °C and evaporation temperature app. 22 °C. There were demonstrated difficulties in fabrication of the supersonic ejector due to small dimensions of the motive nozzle as well as mixing chamber. Required throat diameter of the motive nozzle was less than 200 μm and the diameter of the mixing chamber was 260 μm. For reported tests conditions the boundary temperature of the on-design operation condition was between 21 – 25 °C. However, the operation of the micro-ejector under off-design operation regime was stable and repeatable. Micro-ejector tests required an indirect method of measurement of critical motive mass flow rate to be applied. The performance line of tested ejector fits to ejectors theory and meet the basic assumptions in terms of thermal capacity and operating temperature. CFD technique used for numerical predictions of the ejector performance fits to experimental measured values with acceptable accuracy.

Effects of influencing factors on the performance and morphology of shock waves in ejectors: A review

This paper presents a detailed literature review on the studies carried out in the last three decades, for understanding the factors affecting the performance of the ejector. An ejector is one of the important components in many industrial applications in the field of refrigerant expansion, circulation of fluids, vacuum creation, etc. From the analysis of the reported works of the ejector, the CFD modeling has proved to be a convenient method for analyzing the complex phenomenon in the ejector like mixing process, turbulence characteristics, shock interactions, and condensation process. The first part of this paper discusses the operation of ejector, flow structure, parameters required for the computational modeling, governing equations, etc. The second part discusses the influence of geometrical parameters and various operating conditions on the ejector performance. The shape and position of shock waves in the ejector for various operating conditions are also narrated under the same section. Third part of this paper is devoted to discussions on advances in modeling to be considered for the performance improvement of ejectors. Finally, the paper concludes with clear guidelines for the effective ejector modeling. Future scope of ejector research, pathways to progress, etc., mentioned in the conclusion section should help researchers and designers in this field.

Studies on Shock Wave Structures in Supersonic Ejector and Its Influence on Ejector Performance

Supersonic ejectors are an economically feasible and environmentally friendly technology. Shock wave structures significantly affect the ejector performance. In the present work, the first shock wave structures in a supersonic ejector were analyzed with experimental and numerical methods. The experimental results by the Schlieren method were used to verify the accuracy of the numerical simulation results. Then the influence of the inlet pressure on the first shock wave structures inside the ejector was analyzed under critical operating conditions. The numerical simulation results showed that the dimensionless length and height of the first shock wave inside the ejector increase with the increase of the primary pressure and decrease with the increase of the secondary pressure. Meanwhile, the relationship between the performance of the ejector and the shock structures was established, the entrainment ratio is positively correlated with the first shock wave aspect ratio and has a good linear relationship. The results may be beneficial to reveal the ejector’s working mechanism and design high performance ejectors in the future.

Investigation on key geometries optimization and effect of variable operating conditions of a transcritical R744 two-phase ejector

There was no literature that involved the combined investigation on the key geometries optimization and the effect of variable operating conditions (temperature, pressure and dryness fraction of primary and secondary flows) for a R744 two-phase ejector. In this paper, CFD simulation on geometries optimization and effect of variable operating conditions of a transcritical R744 two-phase ejector was carried out for the first time. Firstly, each of three geometries of area ratio (AR), nozzle exit position (NXP) and constant-area mixing chamber length (L2) was optimized to determine their relative sensitivity on ejector performance. Then, two or three geometries under different optimization orders were optimized. Finally, the effects of temperature, pressure and dryness fraction of primary and secondary flows as well as back pressure on ejector performance were analyzed based on the optimal ejector geometries. The results showed that: (1) the relative sensitivity of entrainment ratio (ER) to AR is the highest with value of 44.56%, followed by NXP and L2; (2) optimizing two or three of these parameters under different optimization sequences can achieve certain optimization effect with ER improvement within 5.96%–33.91%, but the result depends on the optimization order; (3) the effect of dryness fraction of the primary flow on the ejector performance is greater than that of temperature; (4) the change of secondary flow pressure has a greater impact on the ejector ER as compared to the dryness fraction of the secondary flow; (5) not only increasing the primary and secondary flow pressure but also reducing the back pressure is conducive to improving the ejector performance.