WATER QUANTIFICATION FROM SPRAYER NOZZLE BY USING PARTICLE IMAGE VELOCIMETRY ( PIV ) VERSUS IMAGING PROCESSING TECHNIQUES

Characteristics of the sprayer nozzles are important criteria in the application of different chemicals (pesticides, fungicides etc.) for different cropping systems, because of their direct effect on the efficiency of these chemical products. Previous research showed that uniform distribution of spray is very important, 30% of agricultural pesticide sprayed is lost during spraying due to the non-uniformity of droplet size and offtarget drift (Bahrouni et al., 2008; Miller and Ellis, 2000). The structure of the spray deposits can be affected by velocity, volume and size of the droplets (Guler et al., 2007). Therefore, the study of the spray characteristics is very important for the ideal nozzle-velocity combination, which will optimize the spray efficiency with the appropriate dosage to the right targets (pests or insects on leaves etc.). In other words, parameters of spraying patterns such as the spray velocity, size of the droplet, volume distribution pattern, entrained air characteristics, structure of individual droplets, spray angle and spray structure play important roles for the efficiency of the agro-chemical application process (Miller and Ellis, 2000). Our overall research goal is to examine the liquid jet properties during spraying processes to analyze the liquid distribution and uniformity of spraying patterns on plants with the objective of improving the sprayer nozzles design. This requires maximizing the uniformity of applied spray as a function of operating pressures, nozzle parameters and wind effects. There are few papers in the literature dealing with this kind of issue except the works of Marcal and Cunha (2008) and Sudheer and Panda (2000). Marcal and Cunha (2008) used water sensitive papers (WSP) coupled with image processing technique to observe the fraction of spray coverage, homogenity parameters, stains and droplet numbers. The number of droplets per area was calculated using different scanning resolution and data was then compared with manually counted spots on WSP, but this method can measure the spray fraction coverage ranging from 7 to 50%. However, this method was not found to be suitable for more than 50% coverage on WSP due to submergence of droplets (droplets merging with each other). Sudheer and Panda (2000) measured the droplet size produced by the sprinkler nozzles using image processing technique from Otsu (1979) to determine the threshold in image processing. The droplet size was also measured with the Pellet method (Sudheer and Panda, 2000) in a laboratory to compare the results of the images with actual results. This study revealed that droplet sizes less than 0.90 mm could not be measured in using the image processing technique but larger droplet sizes could be with more accuracy (Sudheer and Panda, 2000). In this paper, we want to use the lab scale research in introducing the new imaging technique which is carried out through the acquisition of necessary information to support Pak. J. Agri. Sci., Vol. 55(1), 203-210;2018 ISSN (Print) 0552-9034, ISSN (Online) 2076-0906 DOI: 10.21162/PAKJAS/18.6679 http://www.pakjas.com.pk