Spray droplet size distribution and droplet velocity measurements in a firing optical engine

2020 ◽  
Vol 32 (2) ◽  
pp. 023304 ◽  
Author(s):  
Nikhil Sharma ◽  
William D. Bachalo ◽  
Avinash Kumar Agarwal
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Droplet Velocity ◽  
Velocity Measurements ◽  
Spray Droplet ◽  
Optical Engine

Numerical Simulation and Experiment of Atomization Field of Fan-Shaped Atomization Nozzle for Plant Protection UAV

2021 ◽  
Vol 14 ◽  
Author(s):  
Maohua Xiao ◽  
Yuanfang Zhao ◽  
Zhenmin Sun ◽  
Chaohui Liu ◽  
Tianpeng Zhang
Keyword(s):  
Numerical Simulation ◽  
Size Distribution ◽  
Droplet Size ◽  
Plant Protection ◽  
Cone Angle ◽  
Droplet Size Distribution ◽  
Droplet Velocity ◽  
Inlet Pressure ◽  
Spray Cone Angle ◽  
Spray Cone

Background: There are drift and volatilization of the droplets produced by the plant protection Unmanned Aerial Vehicle (UAV) under the influence of external wind speed and its flight speed. Objective: It studied the atomization characteristics of its fan-shaped atomizing nozzle under different inlet pressures and inner cavity diameters. Methods: For the start, the Realizable k-ε turbulence model, DPM discrete phase model and TAB breakup model are used to make a numerical simulation of the spray process of the nozzle. Then, the SIMPLE algorithm is used to obtain the droplet size distribution diagram of the nozzle atomization field. At last, the related test methods are used to study its atomization performance, and the changes of atomization angle and droplet velocity under different inlet pressures and inner cavity diameters and the distribution of droplet size are discussed. Results: The research results show that under the same inner cavity diameter, as the inlet pressure increases, the spray cone angle of the nozzle and the droplet velocity at the same distance from the nozzle increase. As the distance from the nozzle increases, the droplet velocity decreases gradually, the droplet size distribution moves to the direction of small diameter, and the droplets in the anti-drift droplet size area increase. Under the same inlet pressure, as the diameter of the inner cavity increases, the spray cone angle first increases and then decreases, and the droplet velocity at the same distance from the nozzle increases. As the distance from the nozzle increases, the droplet velocity decreases gradually, the droplet size distribution moves to the direction of large diameter, and the large size droplets increase, which cannot meet the anti-drift volatilization effect. Conclusion: Under the parameter set in this study, when the inlet pressure is 0.6MPa and the inner cavity diameter is 2mm, the atomization result is the best.

scholarly journals Breakup Processes and Droplet Characteristics of Liquid Jets Injected into Low-Speed Air Crossflow

Processes ◽  
2020 ◽  
Vol 8 (6) ◽  
pp. 676
Author(s):  
Lingzhen Kong ◽  
Tian Lan ◽  
Jiaqing Chen ◽  
Kuisheng Wang ◽  
Huan Sun
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Weber Number ◽  
Droplet Size Distribution ◽  
Droplet Velocity ◽  
Liquid Jet ◽  
Outlet Section ◽  
Low Speed ◽  
Jet Breakup ◽  
Breakup Mode

The breakup processes and droplet characteristics of a liquid jet injected into a low-speed air crossflow in the finite space were experimentally investigated. The liquid jet breakup processes were recorded by high-speed photography, and phase-Doppler anemometry (PDA) was employed to measure the droplet sizes and droplet velocities. Through the instantaneous image observation, the liquid jet breakup mode could be divided into bump breakup, arcade breakup and bag breakup modes, and the experimental regime map of primary breakup processes was summarized. The transition boundaries between different breakup modes were found. The gas Weber number (Weg) could be considered as the most sensitive dimensionless parameter for the breakup mode. There was a Weg transition point, and droplet size distribution was able to change from the oblique-I-type to the C-type with an increase in Weg. The liquid jet Weber number (Wej) had little effect on droplet size distribution, and droplet size was in the range of 50–150 μm. If Weg > 7.55, the atomization efficiency would be very considerable. Droplet velocity increased significantly with an increase in Weg of the air crossflow, but the change in droplet velocity was not obvious with the increase in Wej. Weg had a decisive effect on the droplet velocity distribution in the outlet section of test tube.

Aerial Curtain Spraying for Locust Control: A theoretical Treatment of some of the Factors involved

1950 ◽  
Vol 41 (2) ◽  
pp. 439-457 ◽  
Author(s):  
K. F. Sawyer
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Regular Sequence ◽  
Theoretical Treatment ◽  
Spray Droplet ◽  
Simple Method ◽  
Fine Spray ◽  
Locust Control ◽  
Lethal Doses

This paper deals with the aerial curtain method of spraying flying swarms of locusts with insecticide from aircraft.Equations are developed for calculating the dosage deposited on locusts in single spraying runs under idealised conditions. Graphical methods of solving the equations are described together with a simple method for obtaining the summed effect when a number of spraying runs are carried out in a regular sequence to form an aerial curtain.There is an optimum combination of spray droplet size distribution and spraying height according to the depth and density of the swarm, but good performance can be obtained with a single fixed droplet size distribution. A fine spray is recommended for the attack of flat-topped, shallow swarms, but a coarser spray is required to penetrate adequately into deeper and denser swarms.The efficiency of application of the insecticide solution, calculated as the proportion of lethal doses actually applied to those potentially available, may be as high as 10 per cent., but varies rapidly with spray droplet size and swarm characteristics.The numerical values given may need some modification in the light of further experimental and field data, especially in regard to locust airspeed in the swarm and the effect of droplet size on mortality.

scholarly journals Experimental Study of the Effect of the Expansion Segment Geometry on the Atomization of a Plain-Jet Airblast Atomizer

2021 ◽  
Vol 2021 ◽  
pp. 1-15
Author(s):  
Yi Jin ◽  
Kanghong Yao ◽  
Xiaomin He ◽  
Kai Zhang ◽  
Yunbiao Wang
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Droplet Velocity ◽  
Geometrical Parameters ◽  
Distribution Factor ◽  
Sauter Mean Diameter ◽  
Mean Velocity ◽  
Expansion Segment ◽  
Mean Diameter

In this paper, the idea of adding an expansion segment over traditional airblast atomizer is proposed to improve the spray performance. According to the systematic experiments, the Sauter mean diameter, the droplet size distribution, and the droplet axial mean velocity were obtained to evaluate the spray performance. The correlations between spray performance and four geometrical parameters of the expansion segment which include the length, the angle, the throat area, and position of liquid jet are considered. The atomizer operates at atmospheric pressure and temperature, and the air liquid ratio range is from 0.48 to 2.85. The data of the results were measured by Phase Doppler Particle Analyzer. The results show that more uniform droplet size distribution can be achieved with the addition of expansion segment, and the droplet size distribution factor q of the case adding the expansion segment is 52.8% bigger than that of the case with no expansion segment. q increases as the length and angle of expansion segment increase. The Sauter mean diameter can be reduced by either reducing the length or angle of expansion segment. As for droplet velocity, it is determined that the droplet velocity increases along the radial direction, which is noteworthy because opposite trend is reported for traditional plain-jet atomizers. With an increase of the length, angle, and throat area of the expansion segment, the droplet axial velocity decays.

MODELING DROPLET SIZE DISTRIBUTION NEAR A NOZZLE OUTLET IN AN ICING WIND TUNNEL

2006 ◽  
Vol 16 (6) ◽  
pp. 673-686 ◽  
Author(s):  
Laszlo E. Kollar ◽  
Masoud Farzaneh ◽  
Anatolij R. Karev
Keyword(s):  
Wind Tunnel ◽  
Size Distribution ◽  
Droplet Size ◽  
Droplet Size Distribution ◽  
Nozzle Outlet

CFD simulation of ultrasonic atomization pyrolysis reactor: the influence of droplet behaviors and solvent evaporation

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Jian Wang ◽  
Jichuan Wu ◽  
Shouqi Yuan ◽  
Wei-Cheng Yan
Keyword(s):  
Flow Pattern ◽  
Size Distribution ◽  
Droplet Size ◽  
Cfd Simulation ◽  
Collection Efficiency ◽  
Great Influence ◽  
Droplet Size Distribution ◽  
Solvent Evaporation ◽  
Droplet Collision ◽  
Ultrasonic Atomization

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.

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