The Venturi Burner optimizes the mixing effect of gas and air through its unique structural design, thus improving combustion efficiency. The following are the key mechanisms and improvement directions to improve combustion efficiency combined with engineering practice and theoretical analysis:
I. Core Functions of the Venturi Effect
1. Gas Mixing Optimization
-The Venturi tube's contraction-expansion structure creates a low-pressure zone at the throat, utilizing pressure differentials to rapidly draw in primary air and mix it with fuel gas through premixed combustion, effectively reducing localized over-combustion or under-combustion.
-Homogeneous mixing directly impacts combustion completeness; the Venturi design shortens mixing paths while minimizing emissions of unburned hydrocarbons (UHC) and CO.
2. Turbulence Enhancement
-High-speed airflow generates intense turbulence at the throat, breaking up fuel molecular clusters to increase oxygen contact area and accelerate reaction rates.
II. Impact of Structural Parameters on Efficiency
1. Lumen Diameter Ratio and Contraction/Elevation Angles
-The lumen diameter ratio (LDR) between the throat diameter and inlet diameter determines air intake volume, requiring adjustment according to gas calorific value. For example, high-calorific-value gases require a larger LDR to accommodate more air.
-The contraction angle (typically 15°-30°) and elevation angle (5°-15°) affect flow loss; excessive angles may cause airflow separation and reduce mixing efficiency.
2. Multi-stage Venturi Design
-Multi-stage Venturi configurations (e.g., dual-throat structures) can further refine the mixing process, making them suitable for wide-load regulation scenarios to prevent insufficient mixing during low-load conditions.
III. Optimization of Operating Conditions
1. Air-Fuel Ratio Control
-Venturi burners typically rely on their own pressure differential to regulate air-fuel ratio, but require coordination with gas pressure stabilizers (e.g., pressure regulators) to prevent fluctuations. The ideal air-fuel ratio approaches stoichiometric levels (e.g., approximately 10:1 for natural gas).
-Installing oxygen sensors with feedback systems enables dynamic adjustment of air-fuel ratio to adapt to variations in gas composition.
2. Preheating Air/Gas
-Preheating primary air (e.g., utilizing flue gas waste heat) can enhance combustion temperature and shorten ignition delay time, though excessive temperatures must be avoided to prevent increased NOx emissions.
IV. Auxiliary Technology Enhancements
1. Vortex Device or Blade Guiding
-Installing vortex blades at the Venturi tube outlet enhances airflow rotation, prolongs residence time, and ensures complete combustion.
2. Tiered Combustion with Low Nitrogen Design
-Introducing secondary air into the combustion zone reduces peak flame temperature, minimizes thermal NOx formation while maintaining high efficiency.
V. Maintenance and Adaptive Improvements
1. Anti-clogging Design
-Ash accumulation or coking in the throat can disrupt the Venturi effect. Regular cleaning or wear-resistant coatings (e.g., Al₂O₃ ceramic) should be implemented.
2. Fuel Adaptability Expansion
-For different gas types (e.g., liquefied petroleum gas, biogas), adjustable throat components or nozzle aperture adjustments can be made to match specific characteristics.
The efficiency of Venturi burners stems from their self-suction mixing and turbulence-enhanced physical mechanisms, which require integration with structural optimization, intelligent control, and maintenance strategies. Future development directions include 3D-printed customized flow channels and AI-driven real-time air-fuel ratio regulation to break through traditional design limitations. In practical applications, design parameters must be comprehensively optimized based on fuel type, load requirements, and environmental compliance standards.
