ENVIRONMENTAL ENGINEER Health, Engineering and Sciences (HES) - - PowerPoint PPT Presentation

Ian P. Craig BSc MSc PhD Cranfield

ENVIRONMENTAL ENGINEER

Centre for Pesticide Application and Safety (C-PAS) Gatton Campus, University of Queensland (UQG) mob 0419 636691 Health, Engineering and Sciences (HES) University of Southern Queensland (USQ) craigi@usq.edu.au

Rotary Nozzle Development and Testing

Ligament formation Edward Bals

Controlled Droplet Application (CDA)

Direct Droplet Formation possible at very low flowrates Sheet Breakup Graham Matthews

• Stacked discs have fine ‘v’ grooves which are prone to blockage
• A row of teeth is only possible about every 5mm (with each cupped disc)
• Rather than a groove leading to a tooth arrangement, the SP nozzle has

individual pins every ~1mm …. so ~5x flowrate should be available

Malvern 2600 laser diffraction analyser

22

IN 2003, IN 2003, I PATENTED A I PATENTED A NEW NEW “SPINNING PINS” NOZZLE “SPINNING PINS” NOZZLE FOR AERIAL FOR AERIAL APPLICATION OF PESTICIDES, (WHICH I APPLICATION OF PESTICIDES, (WHICH I HOPE HOPE WILL HELP WILL HELP WORLD FOOD SECURITY). WORLD FOOD SECURITY). so you see - I’m not actually all that green !

23 Craig, I.P. Hewitt, A, and Terry, H. 2014. Rotary atomiser design requirements for

• ptimum pesticide application efficiency.

Crop Protection 66 34-39 Craig, I. 2003. THE SPINNING PINS (SP) Nozzle; A New Controlled Droplet Applicator for Aircraft. IP Australia Application Number AU200163597B2 Patent Number 779967. Published 2003.02.27 Schematic diagram (based on stroboscopic light observation)

• f near-monosized droplet

formation, via controlled fluid ligament breakup

25

About 3 million tonnes pesticides (ai) produced globally every year

<0.1% 1% ? <0.1% AE

~ application efficiency (AE) is thought to be substantially less than 1%

(1000s) (100s) (10s) (droplet #/cm2)

Dr Steve Parkin

200µm

Droplet size distribution (triangles) from a spinning disc with sharp teeth, recorded using a PMS OAP-260 probe. For comparison, computer generated spectra with VMD 200µm have been added. The solid line represents a 200µm VMD spray with log span 0.1, typical for spinning discs. The dashed line represents a 200 µm VMD spray with log span 0.25, typical for hydraulic nozzles, and rotary cage atomisers such as the Micronair AU5000.

BCPC ‘medium’ spray (ie. VMD 200µm) ~ has 10% ‘driftables’ (ie. vol < 100µm) the aim with sharp pins is reduce this to zero

h = release height u = mean windspeed u* = RMS vertical air motion vs = sedimentation velocity u*/u = turbulence intensity, i

u*/u xpeak h

HIGH TURBULENCE

thin tail vs/u u

plume centreline

thick tail h

LOW TURBULENCE

u xpeak

h = release height u = mean windspeed u* = RMS vertical air motion vs = sedimentation velocity u*/u = turbulence intensity, i h = release height u = mean windspeed u* = RMS vertical air motion vs = sedimentation velocity u*/u = turbulence intensity, i

u*/u xpeak h

HIGH TURBULENCE

thin tail vs/u u

plume centreline

u*/u xpeak h

HIGH TURBULENCE

thin tail vs/u u

plume centreline

thick tail h

LOW TURBULENCE

u xpeak thick tail h

LOW TURBULENCE

u xpeak

Best Management Practice (BMP) for the Australian Cotton Industry

• getting pilots to understand the effect of the Australian summer Dusk Surface

Temperature Inversion (DUSTI), so they that they avoid spraying at dusk !

downwind deposition can be up to 20 times greater in highly stable conditions

http://www.depi.vic.gov.au/agriculture-and-food/farm-management/chemical-use/agricultural-chemical- use/spraying-spray-drift-and-off-target-damage/surface-temperature-inversions

Craig, I.P. 2004 The GDS model – a rapid computational technique for the calculation of aircraft spray drift buffer distances. Computers and Electronics in Agriculture 43 3 235-250