Investigation of the influence of the geometric parameter and the mixing chamber length of an ejector on the origination of the critical mode

1990 ◽  
Vol 59 (1) ◽  
pp. 917-919
Author(s):  
E. G. Zaitsev
Keyword(s):  
Geometric Parameter ◽  
Critical Mode ◽  
Chamber Length ◽  
Mixing Chamber

Triple-Choking Model for Ejector

2010 ◽  
Vol 2 (2) ◽  
Author(s):  
J. Sargolzaei ◽  
M. R. Pirzadi Jahromi ◽  
E. Saljoughi
Keyword(s):  
Theoretical Models ◽  
Mixing Efficiency ◽  
Governing Equations ◽  
Critical Mode ◽  
Cross Sectional ◽  
New Approach ◽  
Mode Operation ◽  
Operation Conditions ◽  
Mixing Chamber ◽  
Good Agreement

In this study, a 1D analysis has been presented for the prediction of ejector performance at critical mode operation. The new triple-choking model has been developed using the governing equations of the compressible fluids and thermodynamics properties based on the frictional adiabatic fluid study. A new approach has been introduced to consider the frictional effects on the mixing efficiencies by extending the 1D ejector theory. A very good agreement has been reported for the R141b and steam experimental data at critical mode operation. Furthermore, simulated results have been compared with some of the recent theoretical models. In addition, the influence of operation conditions on the ejector performance and the required cross-sectional area of the mixing chamber has been showed. Finally, the influence of the operation conditions (such as generator, condenser, and evaporator temperatures) and the size of ejector on the mixing efficiency have been studied.

Investigation of Two-Phase Flow in an Effervescent Atomizer

2014 ◽  
Author(s):  
Mona Hassanzadeh Jobehdar ◽  
Aly H. Gadallah ◽  
Kamran Siddiqui ◽  
Wajid A. Chishty
Keyword(s):  
Internal Combustion Engines ◽  
Two Phase Flow ◽  
Separation Bubble ◽  
Phase Flow ◽  
Two Phase ◽  
Chamber Length ◽  
Flat Base ◽  
Mixing Chamber ◽  
Wide Range ◽  
Effervescent Atomizer

Aerated-liquid atomization, also called “effervescent atomization”, is a technique that has a wide range of applications such as gas turbine combustors, internal combustion engines, furnaces and burners, and pharmaceutical sprays. We report on an experimental study conducted to investigate the two-phase flow in an Effervescent atomizer. A novel aerator tube base was implemented and tested. It is observed that the novel configuration suppresses the separation bubble at the trailing edge and results in more uniform and smaller bubbles compared to the standard flat base aerator. It has been found that the more uniform and smaller bubbles are generated as the mixing chamber length is reduced. It is concluded that by using a conical base aerator and by reducing the mixing chamber length, the spray steadiness and the atomization process can be significantly improved.

Experimental Determination of Geometric Parameters for an Annular Injection Type Supersonic Ejector

2006 ◽  
Vol 128 (6) ◽  
pp. 1164-1171 ◽  
Author(s):  
Sehoon Kim ◽  
Sejin Kwon
Keyword(s):  
Secondary Flow ◽  
Static Pressure ◽  
Area Ratio ◽  
Geometric Parameters ◽  
Cross Sectional ◽  
Chamber Length ◽  
Supersonic Ejector ◽  
Mixing Chamber ◽  
Flow Pressure ◽  
Contraction Angle

The effects of four geometric parameters of an annular injection supersonic ejector, namely, the primary nozzle exit-to-throat area ratio, the contraction angle of the mixing chamber, the cross-sectional area and L/D ratio of the second-throat on the performance parameters including the secondary flow pressure, the starting pressure and unstarting pressure were investigated experimentally. The starting pressure exhibits linearly proportional dependence on the throat area ratio when the mixing chamber length is less than a certain critical value. For a longer mixing chamber, the starting pressure is proportional to the mixing chamber length while the unstarting pressure depends on the throat area ratio only. The geometric parameters of the second-throat do not affect the static pressure of the secondary flow. This implies that the secondary flow is aerodynamically choked in the mixing chamber and the static pressure of the secondary flow is determined by the choking condition since the mixing chamber of the annular injection ejector is relatively long. Based on the findings by the experiment, a simplified analytical model was proposed to predict the secondary flow pressure. The predicted secondary flow pressure agrees reasonably well with the measurement for a small contraction angle of the mixing chamber.

scholarly journals Numerical Investigation on the Performance of Two-Throat Nozzle Ejectors with Different Mixing Chamber Structural Parameters

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 6900
Author(s):  
Fatong Jia ◽  
Dazhang Yang ◽  
Jing Xie
Keyword(s):  
Structural Parameters ◽  
Operational Performance ◽  
Water Heater ◽  
Chamber Length ◽  
Heat Pump Water Heater ◽  
Mixing Chamber ◽  
Optimal Value ◽  
Nozzle Geometries ◽  
Converging Angle ◽  
Chamber Diameter

In this study, the effects of the mixing chamber diameter (Dm), mixing chamber length (Lm) and pre-mixing chamber converging angle (θpm) were numerically investigated for a two-throat nozzle ejector to be utilized in a CO2 refrigeration cycle. The developed simulated method was validated by actual experimental data of a CO2 ejector in heat pump water heater system from the published literature. The main results revealed that the two-throat nozzle ejectors can obtain better performance with Dm in the range of 8–9 mm, Lm in the range of 64–82 mm and θpm at approximately 60°, respectively. Deviation from its optimal value could lead to a poor operational performance. Therefore, the mixing chamber structural parameters should be designed at the scope around its optimal value to guarantee the two-throat nozzle ejector performance. The following research can be developed around the two-throat nozzle geometries to strengthen the ejector performance.

Numerical investigation on the influence of mixing chamber length on steam ejector performance

2020 ◽  
Vol 174 ◽  
pp. 115204 ◽  
Author(s):  
Jingming Dong ◽  
Qiuyu Hu ◽  
Mengqi Yu ◽  
Zhitao Han ◽  
Wenbin Cui ◽  
...  
Keyword(s):  
Numerical Investigation ◽  
Chamber Length ◽  
Steam Ejector ◽  
Mixing Chamber

Simulation and experiment study of the self-excited oscillating mixer with abrasive jet used for the descaling of rusty steel

2019 ◽  
Vol 233 (5) ◽  
pp. 1109-1127 ◽  
Author(s):  
Hui Ji ◽  
Xiurong Cao ◽  
Songlin Nie ◽  
Fanglong Yin
Keyword(s):  
Simulation Experiment ◽  
Inlet Pressure ◽  
Abrasive Water Jet ◽  
Strip Steel ◽  
Chamber Length ◽  
Mixing Chamber ◽  
Excited Oscillation ◽  
Simulation And Experiment ◽  
Jet Characteristics ◽  
Chamber Diameter

A novel self-excited oscillating mixer is developed for the descaling of strip steel, which synthesizes the post-mixed abrasive water jet and self-excited oscillation. The realizable k-ɛ model is selected to investigate the effects of different abrasive entrance, inlet pressure, mixing chamber diameter, and length on the jet characteristics. Meanwhile, the effects of different inlet pressure and target distance on the outlet velocities for two kinds of mixers (including the developed mixer and conventional post-mixing mixer) with or without abrasive jet are investigated through simulation. Experiment as well as simulation results exhibited: (1) The oblique abrasive entrance can accelerate the mixture of water and abrasive due to its larger turbulent kinetic energy, and its outlet velocity is larger than that of radial and axial abrasive entrances. (2) For the developed mixer, the outlet velocity is preferable when the mixing chamber diameter is about 40–50 mm and the mixing chamber length is 20 mm. (3) The descaling efficiency of the developed mixer is superior to that of conventional post-mixing mixer. The research will lay foundation to optimize the structure of self-excited oscillating mixer for the descaling of rusty steel.

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