Effect of mixing on the performance of wet steam ejectors

Ariafar, Kavous; Buttsworth, David; Al-Doori, Ghassan; Malpress, Ray

doi:10.1016/j.energy.2015.10.082

Cited by 64 publications

(17 citation statements)

References 28 publications

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“…However, the default wet steam model was less satisfactory to predict the condensation process because their comparison results presented that the CFD model predicted a very earlier Wilson point than experimental data. Ariafar et al [39] also solved the non-equilibrium condensation in a steam ejector using the ANSYS FLUENT. Their numerical results showed that the entrainment ratio and critical back pressure calculated by the wet steam model were 10% and 7% higher than that for the ideal gas law, respectively.…”

Section: Introductionmentioning

confidence: 99%

Performance of supersonic steam ejectors considering the nonequilibrium condensation phenomenon for efficient energy utilisation

et al. 2019

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Supersonic ejectors are of great interest for various industries as they can improve the quality of the low-grade heat source in an eco-friendly and sustainable way. However, the impact of steam condensation on the supersonic ejector performances is not fully understood and is usually neglected by using the dry gas assumptions. The non-equilibrium condensation occurs during the expansion and mixing process and is tightly coupled with the high turbulence, oblique and expansion waves in supersonic flows. In this paper, we develop a wet steam model based on the computational fluid dynamics to understand the intricate feature of the steam condensation in the supersonic ejector. The numerical results show that the dry gas model exaggerates the expansion characteristics of the primary nozzle by 21.95%, which predicts the Mach number of 2.00 at the nozzle exit compared to 1.64 for the wet steam model. The dry gas model computes the static temperature lower to 196 K, whereas the wet steam model predicts the static temperature should above the triple point due to the phase change process. The liquid fraction can reach 7.2% of the total mass based on the prediction of the wet steam model. The performance analysis indicates that the dry gas model overestimates a higher entrainment ratio by 11.71% than the wet steam model for the steam ejector.

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Section: Introductionmentioning

confidence: 99%

Performance of supersonic steam ejectors considering the nonequilibrium condensation phenomenon for efficient energy utilisation

et al. 2019

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“…The wet steam model can better predict the actual flow conditions and the simulation results are closer to the experimental values [46,47]. Nevertheless, the research of comparing the CFD simulation values with the experimental values studied by Moore et al [48], it was concluded that the simulated value of the ideal gas model is closer to the experimental value and can better reflect the fluid flow characteristics than the wet steam model in the double-choked flow mode. Garcia del Valle [38] pointed out that there was no significant difference between the ideal gas and the real gas in the linear axisymmetric supersonic ejector.…”

Section: Numerical Simulation Methodsmentioning

confidence: 83%

A Steam Ejector Refrigeration System Powered by Engine Combustion Waste Heat: Part 1. Characterization of the Internal Flow Structure

et al. 2019

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With the escalating production of automobiles, energy efficiency and environmental friendliness have always been a major concern in the automotive industry. In order to effectively lower the energy consumption of a vehicle, it is essential to develop air-conditioning systems that can make good use of combustion waste heat. Ejector refrigeration systems have become increasingly popular for this purpose due to their energy efficiency and ability to recycle waste heat. In this article, the elements affecting the performance of a typical ejector refrigeration system have been explored using both experimental and numerical approaches. For the first time, the internal flow structure was characterized by means of comprehensive numerical simulations. In essence, three major sections of the steam ejector were investigated. Two energy processes and the shock-mixing layer were defined and analyzed. The results indicated that the length of the choking zone directly affects the entertainment ratio under different primary fluid temperature. The optimum enterainment ratio was achieved with 138 °C primary fluid temperature. The shock-mixing layer was greatly affected by secondary fluid temperature. With increasing of back pressure, the normal shock gradually shifted from the diffuser towards the throat, while the shock train length remains lunchanged.

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“…where ρ, u i , p, T and H are the density, velocity, pressure, temperature and total enthalpy, respectively. λ eff is the effective conductivity, purpose, the shear stress transport (SST) k-ω turbulence model is used due to the good accuracy to predict the supersonic nozzle flow [39] and the condensation phenomenon [40]. The equations for these turbulence models are not documented here for brevity, however, they are well documented by Menter [41].…”

Section: Conservation Equations For Gas-liquid Mixturementioning

confidence: 99%

An efficient approach to separate CO2 using supersonic flows for carbon capture and storage

et al. 2019

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Effect of mixing on the performance of wet steam ejectors

Cited by 64 publications

References 28 publications

Performance of supersonic steam ejectors considering the nonequilibrium condensation phenomenon for efficient energy utilisation

Performance of supersonic steam ejectors considering the nonequilibrium condensation phenomenon for efficient energy utilisation

A Steam Ejector Refrigeration System Powered by Engine Combustion Waste Heat: Part 1. Characterization of the Internal Flow Structure

An efficient approach to separate CO2 using supersonic flows for carbon capture and storage

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