Transcript Wind tunnel protocol for spray drift assessment Ch. Stainier, F. Lebeau, Destain M.-F., Schiffers B.

Wind tunnel protocol for spray drift
assessment
Ch. Stainier, F. Lebeau, Destain
M.-F., Schiffers B.
Introduction
• The objective of wind tunnel protocol is to
measure spray drift in a reproducible way in
order to evaluate the relative drift potential
of:
– different spray nozzles
– different operating parameters (Pressure,
Height,…)
– different formulation and adjuvants
Introduction
• A normalisation process is underway at the
international level: ISO/DIS 22856/1 within
TC23/SC6. It defines:
– Typical wind tunnel design and layout (2*2m
section, measurement section)
– Examples of measurement methods
– Wind turbulence and heterogeneity thresholds
– Wind tunnel instrumentation (humidity, wind
speed, temperature)
– Typical test reports
Introduction
• Some major hurdles remain as the ISO/DIS
22856/1 protocol is designed for a static
nozzle:
– The long axis of flat fan nozzle is set
perpendicular to air flow, what is not
representative of field drift condition
– The blockage effect of droplet induced air-flow
generate vortexes entraining driftable droplets
resulting in a very specific pattern
– The collectors are prone to saturation due to
local overdoses
Introduction
• The presentation intend to present the
protocol developed in Gembloux which is
based on traversing
– an ISO/DIS 22856/1 wind tunnel
– a moving nozzle with controllable speed
– fibre glass ground samples
The wind tunnel facility
Low turbidity
Moving boom
Large test
section
Speed up to 6
m/s
Closed loop allows the use
real formulations
Droplet filter
The wind tunnel controllable parameters
• Wind speed 0 - 6 m/s (more with reduced
wind homogeneity)
• Temperature (cooler and heater)
• Relative Humidity (water atomisation)
The Gembloux measurement protocol (aerial view)
0.8m
6m
Wind
direction
(2m/s)
Ground
collector
WIND TUNNEL TEST SECTION
Nozzle
displacement axis
(2m/s)
Spray nozzle
orientation
Standard settings :
Wind speed = 2m/s
RH = 80%
T° = 20°C
P = 3 bar
H=50cm
Glass fibre collectors
Nozzle speed = 2m/s
Results repeatability FF 110 02 (LU)
120
2m/s 50cm 1
2m/s 50cm 2
100
2m/s 50cm 3
parameters
Mean
CV (%)
Wind (m/s)
2.026
0.814
Temp (°C)
19.684
0.137
RH (%)
79.797
0.100
P (bar)
3.093
0.393
80
60
40
20
0
-100
0
100
200
300
400
500
600
Results repeatability
DG 110 04
120
DG 2m/s 1
DG 2m/s 2
100
DG2m/s 3
parameters
mean
CV (%)
Wind (m/s)
1.825
1.162
Temp (°C)
19.207
0.185
RH (%)
78.858
0.177
P (bar)
2.892
0.281
DG 2m/s 4
80
60
40
20
0
-100
0
100
200
300
400
500
600
Results repeatability
XR 110 04
120
XR 2m/s 1
XR 2m/s 2
parameters
mean
CV (%)
Wind (m/s)
2.006
1.048
Temp (°C)
19.287
0.125
RH (%)
68.958
0.132
P (bar)
3.029
0.194
100
XR 2m/s 3
80
60
40
20
0
-100
0
100
200
300
400
500
600
Results wind speed
FF 110 02 (LU)
140
120
2m/s 50cm 2
1m/s 50cm
100
4m/s 50cm
80
60
40
20
0
-100
0
100
200
300
400
500
600
Results wind speed
DG 110 04
120
DG 2m/s 2
100
DG 4m/s
DG 1m/s
80
60
40
20
0
-100
0
100
200
300
400
500
600
Results wind speed
120
XR 2m/s 2
XR 4m/s
100
XR 1m/s
80
60
40
20
0
-100
0
100
200
300
400
500
600
Conclusion
• Repeatability is very satisfactory
• Small differences can be highlighted
• Other drift measurement methods can be
used
• A Gaussian tilting plume model is
developed in order to predict drift of a
moving nozzle