Laser-based Characterisation of Agricultural Sprays D. NUYTTENS & B. SONCK Ministry of the Flemish Community - Agricultural Research Centre (CLO-DVL), Merelbeke (Belgium) Contact: M. DE SCHAMPHELEIRE & W. STEURBAUT Department of Crop Protection, University Ghent (Belgium) K. BAETENS, P. VERBOVEN, B. NICOLAI & H. RAMON Department of Agro-Engineering and Economics, Catholic University of Leuven (Belgium) Objective Measuring the characteristics (droplets: diameter & velocity) of spray nozzles with a PDPA laser based set-up Materials and methods This research was funded by the Ministry of the Flemish Community IWT-Vlaanderen and Federal Public Service Health, Food Chain Safety and Environment, DG Plants, Animals and Food. Some results Volumetric droplet size distribution for different Albuz nozzles Droplet size characteristics D v0.1, D v0.25, VMD, D v0.75 and D v0.9 for different Hardi nozzles and the 5 BCPC reference nozzles Cumulative volumetric droplet velocity distribution for different Hardi nozzles and the 5 BCPC reference nozzles The measuring set-up inside the acclimatization room Three nozzles are selected for each nozzle-pressure combination to be tested. Each nozzle is tested three times. Each scan yields data for at least droplets. The BCPC reference nozzle fine- medium (Lurmark F bar) is used as a reference nozzle to check for the repeatability of the measurements and the measuring equipment. Measurements are made by spraying water with a temperature of about 20 °C. Environmental conditions are kept constant at a temperature of about 20°C and a relative humidity of 60-70%. The nozzle is positioned 50 cm above the measuring point of the PDPA. A different scan trajectory is programmed depending on the type of nozzle to enable the whole of the spray fan to be sampled. RSA OSCILLOSCOPE FIBRE DRIVELASER TRANSMITTERTRANSMITTER RECEIVERRECEIVER PLC SPRAY UNIT Y- direction X-direction Y X Z Z-direction The spray unit PDPA laser 3-D positioning system BCPC:BCPC spray quality class based on droplet size - D v0.1 : 10 percent of the total volume is made up of drops with diameters smaller than this value (μm) - VMD:Volume Median Diameter, 50 percent of the total volume is made up of drops with diameters smaller than this value (μm) - D v0.9 : 90 percent of the total volume is made up of drops with diameters smaller than this value (μm) - V 100 :Percentage of total volume of droplets smaller than 100 μm (%) - V 200 : Percentage of total volume of droplets smaller than 200 μm (%) - D 10, D 20 : Arithmetic mean diameter, Surface mean diameter, Volume mean diameter (μm) - D 30, D 32 :Sauter mean diameter, the diameter of a drop having the same volume to surface area ratio as the total volume of all the drops to the total surface area of all the drops (μm) - NMD: Number mean diameter, 50% of the number of drops is smaller than this value (μm) - RSF: Relative Span Factor - V vol50 : 50 percent of the total spray volume is made of drops with velocities smaller than this value (m.s -1 ) Droplet characteristics (average ± standard deviation) of 32 nozzle- pressure combinations