1 / 35

Spray Droplet Sizing – Understanding the Basics

Spray Droplet Sizing – Understanding the Basics. Brad Fritz USDA ARS Aerial Application Technology Research Unit College Station, Texas. Droplet Diameter. D = droplet diameter V = droplet volume. D. At equal volume with droplets of ½ diameter. 8X the # Droplets.

astin
Download Presentation

Spray Droplet Sizing – Understanding the Basics

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Spray Droplet Sizing –Understanding the Basics Brad Fritz USDA ARS Aerial Application Technology Research Unit College Station, Texas

  2. Droplet Diameter D = droplet diameter V = droplet volume D At equal volume with droplets of ½ diameter 8X the # Droplets

  3. Droplet Volume in the Spray Cloud One 400 µm drop

  4. Droplet Volume in the Spray Cloud 8 - 200 µm drops

  5. Droplet Volume in the Spray Cloud 64 - 100 µm drops

  6. Total Spray Volume Characteristics of total spray volume. NumberDistribution Or VolumeDistribution

  7. Volume vs Number 64X 100µm 8X 200µm 1X 400µm = 8 x V200 V400 = 64 x V100 Total Spray Volume of: V400 + 8(V200)+ 64(V100)

  8. Why Volume vs Count? Count Distribution Volume Distribution We have a total Volume V. V400+ 8*V200 + 64*V100= V We have a total of 73 drops. 1 + 8 + 64 Amount of active product: Volume of spray droplets NOT Numberof droplets 400 µm = 400 µm = 200 µm = 200 µm = 100 µm = 100 µm =

  9. Volume Distribution • DV10 or DV0.1 • DV50or DV0.5 or VMD • DV90 or DV0.9 • %Vol<100µm • %Vol<200µm • How do we get to the numbers we typically deal with? • Using some measurement system, the percentageof the totalsprayvolumethat is ineachdropletsizerangeis determined.

  10. 10% 300 µm

  11. Review • DV10,DV50 or VMD, DV90 • The diameter for which 10% of the total spray volume is made up of droplets of equal orlesser diameter. 100% 10% D This diameter is the DV10

  12. Review 100% 50% D This diameter is the VMD

  13. 150 µm 370 µm 634 µm

  14. 17.2% 4.7%

  15. Relative Span An indicator of the widthof distribution.

  16. VMD = 300µm RS = 0.67 RS = 1.4 RS = 2.2 DV90 510 µm DV90 400 µm DV10 200 µm DV10 90 µm DV10 165 µm DV90 435 µm

  17. Take Home • At equal volume: • Halving the diametercreates 8Xdroplets • Quarteringcreates 64Xdroplets • The smaller the diameter, the greater the number of droplets, and the less control you have over them. • Volume Distribution corresponds to available product and efficacy • DV10, DV50 (VMD), DV90, RS, %<100µm, etc…

  18. Spray Measurement

  19. Measurement Groundspeed?

  20. It’s All About How You Measure… Likely Will Get Different Exact Numbers

  21. It’s All Relative Slowest Fastest

  22. Same Concept While Numerical Diameters may differ, Relative Size will be consistent SMALL MEDIUM LARGE

  23. Reference Sprays • Establish Reference Nozzles/Sprays VF/F F/M M/C C/VC VC/XC

  24. Reference Nozzle Curves EXTREMELY COARSE VERY COARSE COARSE MEDIUM FINE VERY FINE

  25. MEDIUM Spray DV10: 80 to 110 um DV50: 190 to 280 um MEDIUM Spray DV10: 105 to 155 um DV50: 230 to 350 um

  26. Be Cautious with Numbers ASABE S572 Standard

  27. Labels – Beware of Conflict Better to go by Classthan Size

  28. Take Home • Droplet Size Number can vary from lab to lab, company to company…. • BUT • Droplet Size Classification is consistent.

  29. Differences Within a Class MEDIUM Spray – USDA ARS Current Nozzle Models 429 280 MEDIUM 180 141

  30. 2 MEDIUM Sprays Medium #1 8°, 60 psi and 150 mph DV10 = 184 VMD = 322 DV90 = 543 %<100um = 2.7% Medium #2 38°, 60 psi and 150 mph DV10 = 146 VMD = 282 DV90 = 433 %<100um = 5.6% CP11TT with 4015 FF

  31. 2 MEDIUM Sprays 429 MED#1 MED#1 MEDIUM 280 180 141

  32. What Happens in the Field? Downwind Drift Medium #1 1.6% Medium #2 2.4% AGDISP

  33. Take Home Consider Size Class first. Then Optimize setups to decrease fines. Remember Not all MEDIUM or COARSE sprays are equal

More Related