Spray volume distribution pattern and droplet size spectrum from ceramic nozzles

Mateus P Massola,Elton F Dos Reis,Anderson Da S Umbelino,Marcos P De O Martins,Vandoir Holtz

doi:10.1590/1807-1929/agriambi.v22n11p804-809

Abstract

ABSTRACT Droplet size spectrum and uniformity of spray volume distribution are important parameters for selecting spray nozzles. The objective of this study was to evaluate the average spray volume distribution and droplet size spectrum from ceramic nozzles. The spray volume distribution pattern was evaluated on a test table for hydraulic spray nozzles using spray heights of 0.4, 0.5, 0.6, 0.7, and 0.8 m, and working pressures of 500, 600, and 700 kPa. Computer simulations were used to analyze the spray volume distribution using arrangements of bar heights, working pressures, and spacing between spray nozzles in a bar of 12 m. The droplet size spectrum from the spray nozzles was evaluated using a randomized complete experimental design in a 2 × 3 split-plot arrangement consisting of two types of nozzles (ATR-1.0, and TVI-800075) and three working pressures (500, 600, and 700 kPa), with four replications. The uniformity of spray volume distribution was improved when using ATR-1.0 spray nozzles spaced 0.4 or 0.6 m apart, regardless of the working pressure. Regarding the droplet size spectrum, the volume median diameter decreased with increasing the working pressure for both types of nozzles, reaching 210 μm (ATR-1.0) and 483 μm (TVI-800075). Contrastingly, the percentage of droplets with diameter smaller than 100 μm increased with increasing working pressure; the target coverage presented the same trend, with 8.4% of coverage when using ATR nozzles with working pressure of 700 kPa.

Highlights

RESUMOO espectro de gotas e a uniformidade de distribuição volumétrica são parâmetros importantes na seleção da ponta de pulverização
The experiment was conducted in two steps, one determining the spray volume distribution patterns and other evaluating the droplet size spectrum generated by the different spray nozzles
According to the results found in the present study, spray nozzles must be selected based on the target coverage requirements for an efficient spraying

Summary

Introduction

RESUMOO espectro de gotas e a uniformidade de distribuição volumétrica são parâmetros importantes na seleção da ponta de pulverização. Para o espectro de gotas, o diâmetro da mediana volumétrica diminuiu com o incremento da pressão de trabalho para as duas pontas, atingindo em 210 para a ATR e 483 μm para a TVI. A porcentagem de gotas menores que 100 μm aumentou com o incremento da pressão e a cobertura do alvo apresentaram o mesmo fenômeno, com 8,4% para a ponta ATR na pressão de 700 kPa. The function of spray nozzles is forming droplets; the passing of the pressurized liquid through the tip orifice fractionates the liquid into droplets. According to Freitas et al (2005), the uniformity of spray volume distribution can be evaluated by the coefficient of variation resulting from the overlap of the spray jets. According to Baesso et al (2014), the CH is defined as the ratio between VMD and number median diameter (NMD), which express numerically the droplet uniformity

Objectives

Methods

Results

Conclusion