Question

A tractor sprayer is fitted with 20 hollow cones nozzles to attain application rate of 200 l/hr. During the calibration test, the nozzle flow rate was found to be 1.25 l/min whereas, the rated nozzle flow rate was found to be 0.473 l/min was available at 275 kPa. If the nozzle produces droplets with volume median diameter 200 μm at 1 Mg Pascal, the droplet at the desire flow rate is?

(a) 161 μm

(b) 164 μm

(c) 167 μm

(d) 170 μm

I got this question in an interview.

My doubt stems from Plant Protection Equipments in division Plant Protection Equipments of Farm Machinery

Answer 1

The correct answer is (a) 161 μm

To elaborate: \(\frac{Q1}{Q2}=\sqrt{\frac{P1}{P2}} \)

\(\frac{0.473}{1.25}=\sqrt{\frac{275}{P2}} \)

P2=\(\frac{275*1.25*1.25}{0.473*0.473}\) = 1920.57 kPa

\(\frac{VMD1}{VMD2} = (\frac{P1}{P2})^{\frac{1}{3}} \)

\(\frac{200}{VMD2} = (\frac{1920.57}{1000})^{\frac{1}{3}} \)

VMD2 = 161 μm.