A detailed numerical study on the evolution of droplet size distribution of dibutyl phthalate in a laminar flow diffusion chamber

2020 ◽  
Vol 37 (3) ◽  
pp. 423-433
Author(s):  
Feng Jia ◽  
Zi-Yi Li ◽  
David Y. H. Pui ◽  
Chuen-Jinn Tsai
Author(s):  
Qun Zhang ◽  
Xin Wang ◽  
Rui Kou ◽  
Chaochao Li ◽  
Peng Zhang ◽  
...  

The overall process and mechanism of the centrifugal pre-film atomization with double swirling flow were studied using the methods of large Eddy simulation and volume of fluid. The atomization process includes a centrifugal jet under the primary swirl and a pre-film atomization under the two-stage counter-rotating swirl at the venturi outlet. The fuel is ejected from the outlet of the centrifugal nozzle and undergoes the transient process of reaching the venturi throat. The breaking mechanism of liquid film in this process is the same as that of the formation mechanism of the mushroom-shaped tip of liquid jet. The numerical simulation results are highly consistent with the experimental results. For the formation and development of the liquid film on the venturi wall, collision and wave action promote the expansion of the liquid film. At the outlet position of the venturi tube, the short wave mode and the two-stage reverse swirling structure play major roles in the fragmentation process of the flake liquid film, which coincides with the flow characteristics given by the experiment. It is found that the spray cone angle increases as the fuel flow rate increases, and the numerical results are basically consistent with the predicted values of the empirical formula under different fuel flow rates. The droplet size distribution showed a Poisson distribution during the atomization of centrifugal jets and pre-film, and the peak position and variation trend of the droplet size distribution at the outlet of the venturi tube were basically consistent with experimental results.


2006 ◽  
Vol 16 (6) ◽  
pp. 673-686 ◽  
Author(s):  
Laszlo E. Kollar ◽  
Masoud Farzaneh ◽  
Anatolij R. Karev

Author(s):  
Jian Wang ◽  
Jichuan Wu ◽  
Shouqi Yuan ◽  
Wei-Cheng Yan

Abstract Previous work showed that particle behaviors in ultrasonic atomization pyrolysis (UAP) reactor have a great influence on the transport and collection of particles. In this study, the effects of droplet behaviors (i.e. droplet collision and breakage) and solvent evaporation on the droplet size, flow field and collection efficiency during the preparation of ZnO particles by UAP were investigated. The collision, breakage and solvent evaporation conditions which affect the droplet size distribution and flow pattern were considered in CFD simulation based on Eulerian-Lagrangian method. The results showed that droplet collision and breakage would increase the droplet size, broaden the droplet size distribution and hinder the transport of droplets. Solvent evaporation obviously changed the flow pattern of droplets. In addition, both droplet behaviors and solvent evaporation reduced the collection efficiency. This study could provide detail information for better understanding the effect of droplet behaviors and solvent evaporation on the particle production process via UAP reactor.


2014 ◽  
Vol 32 (14) ◽  
pp. 1655-1663 ◽  
Author(s):  
Leila Kavoshi ◽  
Mohammad S. Hatamipour ◽  
Amir Rahimi ◽  
Mehdi Momeni

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1233
Author(s):  
Umair Jamil Ur Rahman ◽  
Artur Krzysztof Pozarlik ◽  
Thomas Tourneur ◽  
Axel de Broqueville ◽  
Juray De Wilde ◽  
...  

In this paper, an intensified spray-drying process in a novel Radial Multizone Dryer (RMD) is analyzed by means of CFD. A three-dimensional Eulerian–Lagrangian multiphase model is applied to investigate the effect of solids outlet location, relative hot/cold airflow ratio, and droplet size on heat and mass transfer characteristics, G-acceleration, residence time, and separation efficiency of the product. The results indicate that the temperature pattern in the dryer is dependent on the solids outlet location. A stable, symmetric spray behavior with maximum evaporation in the hot zone is observed when the solids outlet is placed at the periphery of the vortex chamber. The maximum product separation efficiency (85 wt %) is obtained by applying high G-acceleration (at relative hot/cold ratio of 0.75) and narrow droplet size distribution (45–70 µm). The separation of different sized particles with distinct drying times is also observed. Smaller particles (<32 µm) leave the reactor via the gas outlet, while the majority of big particles leave it via the solids outlet, thus depicting in situ particle separation. The results revealed the feasibility and benefits of a multizone drying operation and that the RMD can be an attractive solution for spray drying technology.


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