Discrete element simulation optimization design and testing of low-damage flexible drum threshing elements suitable...

Area of Science:

• Agricultural Engineering
• Mechanical Engineering
• Agronomy

Background:

• Mechanized rice seed harvesting faces challenges with high seed breakage, low threshing efficiency, and significant loss rates.
• Existing threshing elements often fail to meet the stringent requirements for high-quality seed propagation.

Purpose of the Study:

• To design and validate a low-damage, flexible drum-shaped threshing element for improved rice seed harvesting.
• To address issues of seed breakage, low threshing rates, and entrainment loss in mechanized rice seed propagation.

Main Methods:

• Developed a mathematical model to calculate maximum normal impact force during threshing.
• Created a flexible, multi-level hollow stem discrete element rice model for microscopic force analysis.
• Conducted optimization simulations varying drum speed, feeding amount, and threshing gap.

Main Results:

• Optimal parameters: 900 rpm drum speed, 3.734 kg/s feeding amount, 23.214 mm threshing gap.
• Achieved normal force of 18.05 N and tangential force of 12.96 N with a 0.929% loss rate.
• Field tests showed a 55.9% reduction in breakage rate and 15.3% decrease in loss rate compared to traditional steel nail teeth.

Conclusions:

• The flexible drum-shaped threshing element significantly enhances rice seed harvesting quality.
• The designed element effectively reduces seed breakage and loss rates, meeting high-quality harvesting demands.
• This technology offers a viable solution for efficient and gentle mechanized rice seed propagation.