📋 Case Study

Rice Field UAV Spray System Calibration in Vietnam

Clogging during humid monsoon conditions; inconsistent droplet size causing poor coverage on waxy rice leaves

🏗️ Project Overview

Smallholder cooperative deploying multi-rotor UAVs with twin-fluid venturi nozzles for rice blast control

🎯 Challenge

Clogging during humid monsoon conditions; inconsistent droplet size causing poor coverage on waxy rice leaves

🔧 Design Approach

Dual-stage filtration (100μm + 30μm), heated nozzle bodies, real-time viscosity compensation algorithm integrated into flight controller

📐 Design Diagram

AI-generated project design illustration

📐 Key Calculations

Humidity-Adjusted CRI

CRI × (1 − 0.003 × RH%)

Result: 42.1

Baseline CRI was 68 → adjusted for 87% RH

Wettability Index

SurfaceTension / (VMD × ContactAngle)

Result: 0.41

Optimal range: 0.35–0.45 for rice leaf adhesion

📊 Results

Zero clogs over 42 flight hours; 91% deposit retention on upper leaf surface; 37% less active ingredient required per hectare

💡 Lessons Learned

• •Heated nozzles prevent condensation-induced crystallization
• •Wettability index must be validated per crop species

✅ Key Takeaways

• 1Heated nozzles prevent condensation-induced crystallization
• 2Wettability index must be validated per crop species