Numerical study for the influences of primary nozzle on steam ejector performance

Fu, Weina; Li, Yanxia; Liu, Zhongliang; Wu, Hongqiang; Wu, Tongran

doi:10.1016/j.applthermaleng.2016.06.111

Cited by 79 publications

(14 citation statements)

References 22 publications

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“…Due to the symmetric geometry of the ejector, the configuration can be simulated asymmetrically. Two check points are used to investigate the validity and reliability of current numerical simulations, i.e., comparing the numerical results, like pressure and Mach number, at the points with the existing experimental data [11]. It should be mentioned that the amount of entrainment ratio has been also used as a validation parameter for the implemented numerical approach.…”

Section: Resultsmentioning

confidence: 99%

“…Watanawanavet [8] studied the effect of the primary nozzle area ratio on the suction performance, and Zhang et al [9] and Varga et al [10] proposed the use of an oval body in the primary throat to adjust the desired motive mass flow in different working conditions. An intensive study on the effect of the geometrical features of the primary nozzle on the ejector performance has been proposed by Fu et al [11]. For optimization efforts on the mixing chamber geometry, it could be pointed to the research published by Palacz et al [12].…”

Section: Introductionmentioning

confidence: 99%

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Numerical Investigation on the Effects of Operating Conditions on the Performance of a Steam Jet-Ejector

Sabzpoushan¹,

Darbandi²,

Schneider³

2018

Proceedings of the 5th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'18)

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-In this paper, the focus is on an existing steam jet-ejector, in which the primary flow is high pressure superheated steam and the suction flow is a mixture of saturated steam and air. The main goal of this work is to improve the ejector performance via proper setting of its working conditions such as setting motive, suction and discharge pressures and even primary and secondary streams composition, albeit if it is possible. From the computational perspective, the modelling and simulation of fluid flow are very complicated in an ejector because of facing with simultaneous subsonic and supersonic regimes, very high and very low pressure regions close to each other inside the ejector, complex turbulent mixing, and imperative heat transfer conditions. This study aims to improve the entrainment ratio of the existing steam jet-ejector by investigating its performance under different operating conditions and reduce the consumption of motive steam, which is a critical issue in the current human society because of facing with major global warming and water crisis conditions. The results show that by lowering the motive pressure, the achieved entrainment ratio increases up to 51% percent, while the ejector critical back pressure decreases. Obeying the current strategy, the annual water consumption of the vacuum system can be reduced about 3000 m 3 in the current combined power cycle unit.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Numerical Investigation on the Effects of Operating Conditions on the Performance of a Steam Jet-Ejector

Sabzpoushan¹,

Darbandi²,

Schneider³

2018

Proceedings of the 5th International Conference of Fluid Flow, Heat and Mass Transfer (FFHMT'18)

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“…Therefore, they create the red zone-an indication of the air failing to pass through the nozzles. This is due to the fact that the sudden pressure drop imposed by the very small pores leads to the overall pressure of the fluid below the plate to significantly increase [42]. Larger eddies are created across the plate and the chance of a back pressure developing increases.…”

Section: The Effect Of Air Distributor On the Fluid Propertiesmentioning

confidence: 99%

Computational Fluid Dynamics Simulation of Gas–Solid Hydrodynamics in a Bubbling Fluidized-Bed Reactor: Effects of Air Distributor, Viscous and Drag Models

et al. 2019

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In this work, we employed a computational fluid dynamics (CFD)-based model with a Eulerian multiphase approach to simulate the fluidization hydrodynamics in biomass gasification processes. Air was used as the gasifying/fluidizing agent and entered the gasifier at the bottom which subsequently fluidized the solid particles inside the reactor column. The momentum exchange related to the gas-phase was simulated by considering various viscous models (i.e., laminar and turbulence models of the re-normalisation group (RNG), k-ε and k-ω). The pressure drop gradient obtained by employing each viscous model was plotted for different superficial velocities and compared with the experimental data for validation. The turbulent model of RNG k-Ɛ was found to best represent the actual process. We also studied the effect of air distributor plates with different pore diameters (2, 3 and 5 mm) on the momentum of the fluidizing fluid. The plate with 3-mm pores showed larger turbulent viscosities above the surface. The effects of drag models (Syamlal–O’Brien, Gidaspow and energy minimum multi-scale method (EMMS) on the bed’s pressure drop as well as on the volume fractions of the solid particles were investigated. The Syamlal–O’Brien model was found to forecast bed pressure drops most consistently, with the pressure drops recorded throughout the experimental process. The formation of bubbles and their motion along the gasifier height in the presence of the turbulent flow was seen to follow a different pattern from with the laminar flow.

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“…Sharifi et al [17] investigated the effect of the nozzle geometry on the performance of the steam ejector by using numerical simulations. Liu and his collaborators [18][19][20][21][22][23] investigated the effects of mixing chamber geometries, suction position, nozzle structures and auxiliary entrainment on the steam ejector performance in the MED-TVC with numerical simulation in their papers. Wang et al [24,25] investigated the effect of the area ratio of the ejector (AR), surface roughness and superheat on condensation in the nozzle.…”

Section: Energies 2018 11 X For Peer Review 3 Of 13mentioning

confidence: 99%

Experimental Investigation of the Steam Ejector in a Single-Effect Thermal Vapor Compression Desalination System Driven by a Low-Temperature Heat Source

et al. 2018

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The paper presents an experimental investigation of a steam ejector in a single-effect thermal vapor compression (S-TVC) desalination system driven by a low-temperature (below 100 °C) heat source. To investigate the performance of the steam ejector in the S-TVC desalination system, an experimental steam ejector system was designed and built. The influences of the nozzle exit position (NXP), operating temperatures, and the area ratio of the ejector (AR) on the steam ejector performance were investigated at primary steam temperatures ranging from 40 °C to 70 °C, and at secondary steam temperatures ranging from 10 °C to 25 °C. The experimental results showed that the steam ejector can work well in the S-TVC desalination system driven by a low-temperature heat source below 100 °C. The steam ejector could achieve a higher coefficient of performance (COP) by decreasing the primary steam temperature, increasing the secondary steam temperature, and increasing the AR. The steam ejector could also be operated at a higher critical condensation temperature by increasing the primary steam temperature and secondary steam temperature, and decreasing the AR. This study will allow S-TVC desalination to compete with adsorption desalination (AD).

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Numerical study for the influences of primary nozzle on steam ejector performance

Cited by 79 publications

References 22 publications

Numerical Investigation on the Effects of Operating Conditions on the Performance of a Steam Jet-Ejector

Numerical Investigation on the Effects of Operating Conditions on the Performance of a Steam Jet-Ejector

Computational Fluid Dynamics Simulation of Gas–Solid Hydrodynamics in a Bubbling Fluidized-Bed Reactor: Effects of Air Distributor, Viscous and Drag Models

Experimental Investigation of the Steam Ejector in a Single-Effect Thermal Vapor Compression Desalination System Driven by a Low-Temperature Heat Source

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