Laser-based Characterisation of Agricultural SpraysLaser-based Characterisation of Agricultural SpraysD. NUYTTENS & B. SONCK

Ministry of the Flemish Community - Agricultural Research Centre (CLO-DVL), Merelbeke (Belgium)

Contact: d.nuyttens@clo.fgov.be

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)

ObjectiveObjectiveMeasuring the characteristics (droplets: diameter & velocity) of spray nozzles with a PDPA laser based set-up

Materials and methodsMaterials 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 resultsSome results Volumetric droplet size distribution for different Albuz nozzles Droplet size characteristics Dv0.1, Dv0.25, VMD, Dv0.75 and Dv0.9

for different Hardi nozzles and the 5 BCPC reference nozzlesCumulative 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 10 000 droplets. The BCPC reference nozzle fine-medium (Lurmark F 110 03 @ 3 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 DRIVE LASER

TRANSMITTER

RECEIVER

3 bar

Liquid temperature

controller

Fluid level

controller

Power supply

Temp. display

Measuring signals

Control signals

3 phase power supply

Pressure regulator

PLC

SPRAYUNIT

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

-     Dv0.1: 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)

-      Dv0.9: 90 percent of the total volume is made up of drops with diameters smaller than this value (μm)

-      V100: Percentage of total volume of droplets smaller than 100 μm (%)

-      V200: Percentage of total volume of droplets smaller than 200 μm (%)

- D10, D20: Arithmetic mean diameter, Surface mean diameter, Volume mean diameter (μm)

-     D30, D32: 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

-      Vvol50: 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