scholarly journals Operation Rule of Steam Ejector and Influence Analysis of Ejection Position

2021 ◽  
Vol 252 ◽  
pp. 02073
Author(s):  
Zhao Jinhui ◽  
Xia Yongbo ◽  
Wang Yufeng ◽  
Liu Tao ◽  
Zhang Lijun

In order to analyze the operation rule of steam ejector used in sewage treatment field, this paper established the mathematical model of steam ejector, simulated the internal flow state, analyzed the influence rule of external parameters on the performance of steam ejector, and analyzed the influence rule of ejector position on the water production ratio of steam ejector multi-effect evaporation desalination system. The research results show that under the same steam ejector structure, as the pressure of the working steam increases, the mixing and disturbance of the working steam and the ejected steam become more intense, and the diamond shock wave structure increases. As the pressure of the ejected steam increases, the momentum exchange effect of the shear blending of working steam and ejected steam is accelerated, and the speed increase rate becomes larger, and the diamond shock wave structure gradually gathers toward the nozzle. As the pressure rise of the ejected steam inlet and outlet increases, the backflow phenomenon near the wall in the mixing chamber becomes more serious, and the diamond shock wave structure is reduced. With the forward movement of the ejector position of the thermal steam compressor, the pressure of the ejected steam increases, and the water production ratio of the steam ejector multi-effect evaporation seawater desalination system shows a downward trend. Therefore, choosing appropriate working condition parameters can effectively improve the working performance of steam ejector and improve its operating efficiency in the field of sewage treatment.

2019 ◽  
Vol 9 (20) ◽  
pp. 4435 ◽  
Author(s):  
Yu Han ◽  
Xiaodong Wang ◽  
Lixin Guo ◽  
Anthony Chun Yin Yuen ◽  
Hengrui Liu ◽  
...  

In general, engine fuel combustion generates 30% waste heat, which is disposed to the environment. The use of the steam ejector refrigeration to recycle the waste heat and transfer them to useful energy source could be an environmentally friendly solution to such an issue. The steam ejector is the main component of the ejector refrigeration system, which can operate at a low-temperature range. In this article, the internal shock wave structure of the ejector is comprehensively studied through the computation fluid dynamics (CFD) approach. The shock wave structure can be subdivided into two regions: firstly the pseudo-shock region consisting of shock train and co-velocity region; secondly the oblique-shock region composed of a single normal shock and a series of oblique shocks. The effect of the shock wave structure on both pumping performance and the critical back pressure were investigated. Numerical predictions indicated that the entrainment ratio is enhanced under two conditions including (i) a longer pseudo-shock region and (ii) when the normal shock wave occurs near the outlet. Furthermore, the system is stabilized as the back pressure and its disturbance is reduced. A critical range of the primary fluid pressure is investigated such that the pumping is effectively optimized.


2021 ◽  
Vol 11 (11) ◽  
pp. 4736
Author(s):  
Saleh Baqer ◽  
Dimitrios J. Frantzeskakis ◽  
Theodoros P. Horikis ◽  
Côme Houdeville ◽  
Timothy R. Marchant ◽  
...  

The structure of optical dispersive shock waves in nematic liquid crystals is investigated as the power of the optical beam is varied, with six regimes identified, which complements previous work pertinent to low power beams only. It is found that the dispersive shock wave structure depends critically on the input beam power. In addition, it is known that nematic dispersive shock waves are resonant and the structure of this resonance is also critically dependent on the beam power. Whitham modulation theory is used to find solutions for the six regimes with the existence intervals for each identified. These dispersive shock wave solutions are compared with full numerical solutions of the nematic equations, and excellent agreement is found.


1967 ◽  
Vol 72 (21) ◽  
pp. 5275-5286 ◽  
Author(s):  
G. Schubert ◽  
W. D. Cummings

1976 ◽  
Vol 10 (1) ◽  
pp. 237-240 ◽  
Author(s):  
Rolf Landauer

2014 ◽  
Vol 40 (6) ◽  
pp. 533-536 ◽  
Author(s):  
I. A. Znamenskaya ◽  
I. E. Ivanov ◽  
I. A. Kryukov ◽  
I. V. Mursenkova ◽  
M. Yu. Timokhin

2016 ◽  
Author(s):  
M. Yu. Timokhin ◽  
H. Struchtrup ◽  
A. A. Kokhanchik ◽  
Ye. A. Bondar

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