Determination of the spray pattern variables of the sprayer nozzles using a linear moving simulator

The aim of this study is to reveal an experimental and statistical model for determining the spray pattern features of the sprayer nozzles. For this aim, a linear moving simulator controlled operating speed was used to carry out the spray pattern tests of sprayer nozzles, and the test results were compared to the patternator outputs. For the spray pattern tests, the hollow cone nozzle discs of 20 in number were tested. The spray application was done at constant spray pressure of 4 bars and spray height of 80 cm. Water sensitive papers were used for the spray pattern trials conducted on the linear moving simulator, and the trials were done at the application volumes of 100 l ha-1, 150 l ha-1 and 200 l ha-1. In the trials relating to the spray pattern, the variables spray actual width, nozzle spray angle, skewness coefficient, kurtosis coefficient, spray pattern uniformity (pattern CV) and volumetric distribution uniformity at the nozzle distances of 50 cm (CV@50 cm) were determined. Besides, the flow rate, spray coverage and droplet density were measured for each of the nozzle discs. In references to the discriminant analysis results, the correctly classification rate of the nozzle discs by the discriminant functions which describes the hollow cone nozzle discs were found as 85.0% for the patternator tests; 88.3%, 91.7% and 95.0% for the simulator tests at the application rates of 100 l ha-1, 150 l ha-1 and 200 l ha-1, respectively. According to the results of the paired-comparing test, the patternator tests and the simulator tests were significantly found different each other excluding the variables of the pattern CV and the skewness from the respect of the spray pattern. But, the correlation between the both of the test methods were determined to be significant. In the trials conducted on the linear moving simulator, the most convenient application volume was found to be 150 l ha-1. In the controlling of the nozzle flow rate, the nozzle discs of 5 in number were confirmed excluding the flow rate limits of ±10%. The nozzle discs of 11 in number in the patternator tests, and 14 in number in the patternator tests in the simulator tests conducted at the application volume of 150 l ha-1 were revealed to be different in the respect of the spray pattern. These nozzle discs fixed by the simulator tests covered the nozzles determined at the tests of the flow rate limit and the patternator. In conclusion, the uneven spray nozzles in terms of the spray pattern were appointed to be confirmed with a high accuracy by the linear moving simulator tests. In terms of the assessments done with regard to the image processing techniques, a significant relationship among of the variables determined on the water sensitive papers was revealed. The among of the gray level (Gs) of the paper images and their spray coverage (Yk, %) variables was found a polynomial relation with high R2 (0.941), (Y_k=-0.00094∙G_s^2-0.143∙G_s+86.03 ) 2017, 97 pages Keywords: Hollow cone nozzle, nozzle spray angle, spray test, application rate