Influences of area ratio and surface roughness on homogeneous condensation in ejector primary nozzle

Wang, Chen; Wang, Lei; Zou, Tao; Zhang, Hailun

doi:10.1016/j.enconman.2017.07.025

Cited by 42 publications

(7 citation statements)

References 31 publications

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“…It showed that the increasing superheated degree of the steam delayed the onset of the condensation and decreased the liquid fraction at the exit of the primary nozzle. In the following study, Wang et al [35] presented the effects of the area ratio between the nozzle exit and nozzle throat and surface roughness on the condensation process inside the primary nozzle. It showed that the increasing area ratio induced a higher liquid mass fraction and high surface roughness resulted in the sharp increase of entropy generation leading to in more energy wastes.…”

Section: Introductionmentioning

confidence: 99%

“…The comparison result indicated that the condensation process improved the mixing between primary and secondary fluids to increase the entrainment ratio. These three simulations in [34][35][36] focused on the condensation in the primary nozzle and ignored the other two important phenomena of the mixing process and shock wave which could be significantly affected by steam condensation.…”

Section: Introductionmentioning

confidence: 99%

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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%

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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“…Wang et al [85] numerically assessed the effect of nozzle exit area ratio and surface roughness on homogeneous condensation. According to this investigation an increase of nozzle exit area ratio reduces condensation intensity and lowers the nozzle static pressure but increases liquid mass fraction.…”

Section: Primary Nozzle Exit Area Ratiomentioning

confidence: 99%

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 1: Single-Phase Ejectors

et al. 2019

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Ejectors used in refrigeration systems as entrainment and compression components or expanders, alone or in combination with other equipment devices, have gained renewed interest from the scientific community as a means of low temperature heat recovery and more efficient energy use. This paper summarizes the main findings and trends, in the area of heat-driven ejectors and ejector-based machines, using low boiling point working fluids, which were reported in the literature for a number of promising applications. An overall view of such systems is provided by discussing the ejector physics principles, as well as a review of the main developments in ejectors over the last few years. Recent achievements on thermally activated ejectors for single-phase compressible fluids are the main focus in this part of the review. Aspects related to their design, operation, theoretical and experimental approaches employed, analysis of the complex interacting phenomena taking place within the device, and performance are highlighted. Conventional and improved ejector refrigeration cycles are discussed. Some cycles of interest employing ejectors alone or boosted combinations are presented and their potential applications are indicated.

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“…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. Liu [26] investigated the AR on the ejector efficiencies and established empirical correlations to predict ejector efficiencies.…”

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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Influences of area ratio and surface roughness on homogeneous condensation in ejector primary nozzle

Cited by 42 publications

References 31 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

Current Advances in Ejector Modeling, Experimentation and Applications for Refrigeration and Heat Pumps. Part 1: Single-Phase Ejectors

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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