Subtopic: Functional requirements, principles of working, construction and operation of manual, animal, tractor and renewable energy operated equipment for tillage, sowing, planting, fertilizer application, inter-cultivation, spraying, mowing, chaff cutting, harvesting and threshing
Question Statement:
Which of the following statements regarding the design and operational mechanics of agricultural sprayers is/are CORRECT?
Options:
(A) The discharge rate of a hydraulic spray nozzle is proportional to the square root of the operating pressure ($\sqrt{P}$)
(B) Increasing the operating pressure decreases the Volumetric Median Diameter (VMD) of the droplets produced
(C) Drift prone droplet fraction increases significantly when droplet diameter is below $100\,\mu\text{m}$
(D) A flat fan nozzle typically provides an elliptical spray pattern with maximum deposit directly under the center of the nozzle
Answer Key:
A, B, C, D
Step-by-Step Solution & Explanation
All given statements are correct based on agricultural spray hydraulics:
- Discharge through a nozzle orifice follows the orifice equation $Q = C_d A \sqrt{\frac{2P}{\rho}} \propto \sqrt{P}$ (Option A is correct).
- Higher pressure increases liquid sheet velocity and shear forces, breaking liquid into smaller droplets and decreasing VMD (Option B is correct).
- Droplets smaller than $100\,\mu\text{m}$ have very low settling velocity and drift extensively with ambient wind currents (Option C is correct).
- Standard flat fan nozzles produce a tapered elliptical distribution, requiring $30\text{--}50\%$ spray pattern overlap for uniform swath deposition (Option D is correct).