Int’l Ground Boom 

l Ground Boom 

Model Developme

Model Developm

David Valcore, Valcore Consulti

David Valcore, Valcore Consult

H. Thistle, USDA H. Thistle, USDA-FS Program Man

FS Program Man

Forest Health Protection Forest Health Protection

Clare Butler Ellis, Silsoe Applic. 

Clare Butler Ellis, Silsoe Applic. 

NIAD-TAG
EMPM July 27, 2010

Background Background

 Current global and EPA Current global and EPA’s regulatory groun

s regulatory grou

drift models are all empirical curve fits to 

drift models are all empirical curve fits to 

deposition predictions deposition predictions –AgDRIFT, PMRA 

AgDRIFT, PMRA 

Campbell), BBA (Ganzelmeir Campbell), BBA (Ganzelmeir-Rottamen), 

Rottamen), 

 Empirical fits limit mitigation options, e.g

Empirical fits limit mitigation options, e.g

review of AgDRIFT (SDTF data) pointed o

review of AgDRIFT (SDTF data) pointed o

account for wind speed. account for wind speed.

 Acknowledged need for longer range drif

Acknowledged need for longer range drif

Endg Species Assessments; [AgDRIFT ma

Endg Species Assessments; [AgDRIFT ma

20-120m]

 Past efforts of AGDISP ground and early 

Past efforts of AGDISP ground and early 

limited fits to field data. limited fits to field data.

 Desire to evaluate mitigation options for 

Desire to evaluate mitigation options for 

Reduction Technology (DRT) program Reduction Technology (DRT) program
EMPM July 27, 2010

‘Silsoe’Drift Mode

Drift Mode

 Chosen per consensus as initial attempt a

Chosen per consensus as initial attempt a

mechanistic model, with potential for long 

mechanistic model, with potential for long 

predictions and mitigation options under 

predictions and mitigation options under 

program program

 Miller, P.C.H.; Hadfield, D.J. (1 Miller, P.C.H.; Hadfield, D.J. (1989) A simulati

989) A simulati

drift from hydraulic nozzles. drift from hydraulic nozzles. Journal of Agricu

Journal of Agricu

Research Research, 42, 135 , 42, 135-142

 enhancements include multiple nozzle bo

enhancements include multiple nozzle bo

speed effects, evaporation module, spray

speed effects, evaporation module, spray

probabilistic inputs probabilistic inputs

 Initial development under UK Pest Safety 

Initial development under UK Pest Safety 

BREAM, for bystander exposure , vapor d

BREAM, for bystander exposure , vapor d

possible sprayer CFD model input/enhanc

possible sprayer CFD model input/enhanc

 Ref C. Butler Ellis, C., (2008) The BREAM proj

Ref C. Butler Ellis, C., (2008) The BREAM proj

developments, TPSA Drift Modeling Workshop

developments, TPSA Drift Modeling Workshop
EMPM July 27, 2010 

Global Effort, Ad hoc Pre

Global Effort, Ad hoc Pre

 USDA FS and ARS, UK Silsoe Applic

USDA FS and ARS, UK Silsoe Applic

UC Davis, Lincoln Ventures NZ, SDT

UC Davis, Lincoln Ventures NZ, SDT

Food Canada. Food Canada.

 Initial plans reported to EMPM Sept

Initial plans reported to EMPM Sept

Status Update Status Update

 Sensitivity Analysis Sensitivity Analysis –key parameters key parameters Prelim. model comparisons to SDTF an

Prelim. model comparisons to SDTF an

data sets data sets

 Investigating multiple nozzle environ e

Investigating multiple nozzle environ e

nozzle wind tunnel nozzle wind tunnel 

 Belgium Un. Leven ~120 reps of field 

Belgium Un. Leven ~120 reps of field 

deposition to 30 m, acceptable protoco

deposition to 30 m, acceptable protoco
EMPM July 27, 2010 

Comparison with subset of Spray 

Comparison with subset of Spray 

Force (SDTF) data Force (SDTF) data

 Different nozzle from previous valid

Different nozzle from previous valid

80 04 (flat fan) 80 04 (flat fan)

 Measurements relating to specific nozz

Measurements relating to specific nozz

 No data for porosity/velocity factors No data for porosity/velocity factors

 Base on previous work with 110 03 no

Base on previous work with 110 03 no

 Different spray liquid Different spray liquid

 Formulation not available in UK so use 

Formulation not available in UK so use 

 Limited no. droplets, for run time = 

Limited no. droplets, for run time = 

curve
EMPM July 27, 2010 

Comparisons to SDTF 

Comparisons to SDTF 

Wind 3.9 m/s Wind 3.9 m/s (FF8004, 50 cm b

(FF8004, 50 cm b

Run 0903 rep 3

0.01

0.1

1

10

0 20 40 60 80 100 120 140 

Distance downwind, m

% app vol

SDTSLAAG

Different nozzle from previous validation work – 80 04

Measurements relating to specific nozzle

No data for porosity/velocity factors

Base on previous work with 110 03 nozzle

Different spray liquid

Formulation not available in UK so ublank EC
EMPM July 27, 2010 

Current Silsoe vs. SDTF tr

Current Silsoe vs. SDTF tr

boom

09 07 v rep 4 - 50" boom height

0.01

0.1

1

10

100

0 20 40 60 80 100 120 140 

Distance downwind

% App vol
EMPM July 27, 2010 

Comparisons vs. SDTF data 

Comparisons vs. SDTF data 

Comparison of Silsoe model and Agdrift up to 400 m 

rep 1

0

0.20.40.60.8

1

1.21.4

0 50 100 150 200 250 300 350 

Distance downwind, m

% App volSilsoe mod

AGDISP sdtf data
EMPM July 27, 2010 

Comparison over all SDTF stan

Comparison over all SDTF stan

0.01

0.1

1

10

0.01 0.1 1 

Measured ground deposit, ml/m2

Predicted ground deposit, 

ml/m2

0.001 0.01 0.1 

Measured ground deposit, % ap

Predicted deposit, % applied
EMPM July 27, 2010 

Sensitivity Analys

Sensitivity Analys

 Large number of inputs needed to r

Large number of inputs needed to 

 Some assumptions and approximat

Some assumptions and approximat

included in the model included in the model

 Are improvements needed to the m

Are improvements needed to the m

adequately represent the processes 

adequately represent the processes 

Understand important paramete

Understand important paramete

 How accurately do the input param

How accurately do the input param

be measured? be measured?
EMPM July 27, 2010 

Nozzle Parameter

Nozzle Parameter

Parameter Parameter Description Description

Beta Initial entrained air velocity as a fraction of lDropmax Number of droplets per size binMdv Minimum droplet volume as fraction Mds, μm Minimum droplet sizeC1, degrees Half wide angleC2, degrees Half narrow angleVl0, m/s Liquid sheet velocityr0, mm Initial distance from nozzleSSFx Air velocity scaling factor (x-directioSSFy Air velocity scaling factor (y-directioLpx, m Porosity length, x -directionLpy, m Porosity length, y -direction
EMPM July 27, 2010 

Nozzle / Environmental Pa

Nozzle / Environmental Pa

Parameter Parameter Description Description

Bin width, Bin width, μmdropsize step/group width dropsize step/group width

Droplet size distribution Droplet size distributionDroplet velocity, m/s Droplet velocity, m/sWbd, degrees C Wbd, degrees C Wet bulb depression Wet bulb depressionh, mHeight of boom above crop Height of boom above crop

Ws, m/s Ws, m/s Wind speed at 3 m above cr

Wind speed at 3 m above cr

Fs, km/h Fs, km/h Forward speed of sprayer Forward speed of sprayer
EMPM July 27, 2010 

Sensitivity to Nozzle po

Sensitivity to Nozzle po

parameters, Min parameters, Min -Max 

Max 

0.01

0.1

1

10

0 50 100 150 20

Distance downwind, m

Ground deposit, ml/m2

Model prediction, original paraSDTF dataModel prediction, minimum dparameters
EMPM July 27, 2010 

Humidity Effect Humidity Effect (0-8o

0.0001

0.001

0.01

0.1

1

0 50 100 15

Distance downwind, m

Ground deposits, % applied volume 
EMPM July 27, 2010 

Effect of minimum drop v

Effect of minimum drop 

(% non-volatile) volatile)

0.001

0.01

0.1

1

0 50 100 1

Distance downwind, m

Ground deposits, % applied volume 
EMPM July 27, 2010 

Boom height effe

Boom height effe

0.0001

0.001

0.01

0.1

1

0 50 100 1

Distance downwind, m

Ground deposits, % applied volume 
EMPM July 27, 2010 

Effect of Wind Spe

Effect of Wind Spe

0.0001

0.001

0.01

0.1

1

0 50 100 15

Distance downwind, m

Ground deposits, % applied volume Wind 

Wind Wind 
EMPM July 27, 2010 

Effect of Beta (entrained ai

Effect of Beta (entrained ai

0.0001

0.001

0.01

0.1

1

0 50 100 

Distance downwind, m

Ground deposits, % applied volume Beta 

Beta PowPow
EMPM July 27, 2010 

Effect of droplet size dis

Effect of droplet size dis

0.0001

0.001

0.01

0.1

1

0 50 100 15

Distance downwind, m

Ground deposits, % applied volume Droplet size distribution as mea

Larger droplets, VMD = 255 um Smaller droplets, VMD = 200 um
EMPM July 27, 2010 

Summary Summary

 Ground deposits predicted by the Silsoe spray drift mod

Ground deposits predicted by the Silsoe spray drift mo

comparison with data from the SD comparison with data from the SDTF and potential for 

TF and potential for 

 Tendency for the model to over predict Tendency for the model to over predict -greatest nearer 

greatest nearer 

 Could potentially be improved by more reliable input data 

modeling spray characteristics. modeling spray characteristics.

 A sensitivity analysis showed th A sensitivity analysis showed the most important param

e most important param

deposits at distances greater than 10 m from the spray

deposits at distances greater than 10 m from the spray

 Those relating to th Those relating to the wider environment e wider environment 

 boom height boom height  wind speed wind speed. evaporation rate, and minimum droplet size evaporation rate, and minimum droplet size

 Those relating to the specific nozzle Those relating to the specific nozzle 

 droplet size distribution droplet size distribution  entrained air velocity entrained air velocity
EMPM July 27, 2010 

Plans

 Additional input parameters refined 

Additional input parameters refined 

Induction (AI) nozzles to compare t

Induction (AI) nozzles to compare t

Wolf and/or Belgium field data Wolf and/or Belgium field data

 Further investigate multiple nozzle 

Further investigate multiple nozzle 

 May require larger wind tunnel e.g. EP

May require larger wind tunnel e.g. EP

 Obtain better nozzle/spray input da

Obtain better nozzle/spray input da

SDTF tank mix for refined comparis

SDTF tank mix for refined comparis

 Possible collaborative CFD model re

Possible collaborative CFD model re
EMPM July 27, 2010 

Acknowledgements Acknowledgements

 Paul C.H. Miller, Silsoe Applic. Unit 

Paul C.H. Miller, Silsoe Applic. Unit 

 Mark Ledson, Crop Life America Mark Ledson, Crop Life America

 QUESTIONS QUESTIONS

 Ref. ASABE 1009781 A Spray Drift Model 

Ref. ASABE 1009781 A Spray Drift Model 

of Ground Deposits from Boom Sprayers, 

of Ground Deposits from Boom Sprayers, 

Ellis, C. Ellis, C.