scholarly journals Modelling Spray Pressure Effects on Droplet Size Distribution from Agricultural Nozzles

2021 ◽  
Vol 11 (19) ◽  
pp. 9283
Author(s):  
Emanuele Cerruto ◽  
Giuseppe Manetto ◽  
Rita Papa ◽  
Domenico Longo
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Droplet Size Distribution ◽  
Drop Size Distribution ◽  
Pressure Effects ◽  
Hollow Cone ◽  
Immersion Method ◽  
Color Code ◽  
Working Pressure ◽  
Custom Made

For spray applications, drop size is the most important feature as it affects all aspects of a phytosanitary treatment: biological efficacy, environmental pollution, and operator safety. In turn, drop size distribution depends on nozzle type, liquid properties, and working pressure. In this research, three nozzles were studied under ordinary working conditions and the effect of pressure on drop size distribution was assessed. The nozzles under test, all from Albuz (France), were an orange hollow cone nozzle ATR 80 (European color code), an air induction flat spray nozzle AVI 11003, and an air induction hollow cone nozzle TVI 8002. The ATR 80 and the TVI 8002 nozzles were tested at four pressure values: 0.3, 0.5, 1.0, and 1.5 MPa; the AVI 11003 nozzle was tested at 0.3 and 0.5 MPa. The drop size measurement technique was based on the liquid immersion method by using a custom-made test bench; spray quality parameters were computed by means of suitable functions written in R language. Results showed that an increase in working pressure caused an increase in drop pulverization regardless of the type of nozzle, and drop pulverization was higher for the turbulence nozzle than for the two air induction nozzles. Based on skewness and kurtosis values, the theoretical gamma distribution was the most adapt to fit the experimental data. The scale parameter showed a decreasing trend with the increase in the pressure, a clear index of higher drop pulverization.

The Measuring of Sodium Droplet Size Distribution and its Impact on the Consequence of Sodium Spray Fire

2017 ◽  
Author(s):  
Wang Guozhi ◽  
Du Haiou ◽  
Wang Rongdong ◽  
Shi Wentao ◽  
Piao Jun
Keyword(s):  
Size Distribution ◽  
Droplet Size ◽  
Input Data ◽  
Drop Size ◽  
Droplet Size Distribution ◽  
Drop Size Distribution ◽  
Liquid Sodium ◽  
The Real ◽  
Temperature And Pressure ◽  
The Impact

The sodium droplet size distribution has significant impact on the consequence of sodium spray fire. And it is fundamental input data for the validation and application of sodium spray fire code. The experiments were carried out in a closed vessel to measure the sodium droplet size distribution. Liquid sodium of 250 °C was sprayed downward into the vessel in the form of sodium droplets through a nozzle with a diameter of 2.4mm. The vessel was inerted by argon gas to prevent the sodium droplets from burning. A real time spray droplet sizing system based on ensemble diffraction technique was used to measure the size of the droplets. And the laser beam was passed through two glass windows on the wall of the vessel to reach the sodium droplets. The tests showed that the sizes of the sodium droplets ranged from 184μm to 1000μm at the nozzle pressure of 0.15MPa. And median diameter was 532μm. The sodium spray fire code named NACOM was used to evaluate the impact of particle size distribution on sodium fire. The measured sodium droplets size distribution and the Nukiyama-tanasama drop size distribution were divided into 11 groups to be used as input data for the NACOM code. A comparison showed that 23% of particles in Nukiyama-tanasama drop size distribution were over 1000μm, while the largest size of particles in the measured sodium droplets was 1000μm. The calculation by NACOM code showed that the trend and value of temperature and pressure in the vessel were similar, so to some extent Nukiyama-tanasama drop size distribution is a good approximation of the real sodium droplet size distribution. However, Nukiyama-tanasama drop size distribution may be unsuitable for application in sodium fire safety analysis, because the temperature and pressure calculated from which was lower than that of the real droplet size distribution.

Airblast Atomization: Studies on Drop-Size Distribution

1982 ◽  
Vol 6 (5) ◽  
pp. 323-327 ◽  
Author(s):  
N. K. Rizk ◽  
A. H. Lefebvre
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Drop Size Distribution

scholarly journals Evaluation of Gamma Raindrop Size Distribution Assumption through Comparison of Rain Rates of Measured and Radar-Equivalent Gamma DSD

2014 ◽  
Vol 53 (6) ◽  
pp. 1618-1635 ◽  
Author(s):  
Elisa Adirosi ◽  
Eugenio Gorgucci ◽  
Luca Baldini ◽  
Ali Tokay
Keyword(s):  
Size Distribution ◽  
Drop Size ◽  
Rain Rate ◽  
Hydrological Cycle ◽  
Drop Size Distribution ◽  
Dual Polarization ◽  
Raindrop Size Distribution ◽  
Radar Measurements ◽  
Raindrop Size ◽  
Rain Rates

AbstractTo date, one of the most widely used parametric forms for modeling raindrop size distribution (DSD) is the three-parameter gamma. The aim of this paper is to analyze the error of assuming such parametric form to model the natural DSDs. To achieve this goal, a methodology is set up to compare the rain rate obtained from a disdrometer-measured drop size distribution with the rain rate of a gamma drop size distribution that produces the same triplets of dual-polarization radar measurements, namely reflectivity factor, differential reflectivity, and specific differential phase shift. In such a way, any differences between the values of the two rain rates will provide information about how well the gamma distribution fits the measured precipitation. The difference between rain rates is analyzed in terms of normalized standard error and normalized bias using different radar frequencies, drop shape–size relations, and disdrometer integration time. The study is performed using four datasets of DSDs collected by two-dimensional video disdrometers deployed in Huntsville (Alabama) and in three different prelaunch campaigns of the NASA–Japan Aerospace Exploration Agency (JAXA) Global Precipitation Measurement (GPM) ground validation program including the Hydrological Cycle in Mediterranean Experiment (HyMeX) special observation period (SOP) 1 field campaign in Rome. The results show that differences in rain rates of the disdrometer DSD and the gamma DSD determining the same dual-polarization radar measurements exist and exceed those related to the methodology itself and to the disdrometer sampling error, supporting the finding that there is an error associated with the gamma DSD assumption.

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