Optimization of Secondary Air Injection in a Wood-Burning Cookstove: An Experimental Study

Area of Science:

• Environmental Science
• Combustion Science
• Public Health

Background:

• Biomass cookstoves are used by nearly 40% of the global population, emitting harmful air pollutants.
• Particulate matter (PM) from cookstoves poses significant health and climate risks.
• Secondary air injection is a potential strategy to reduce PM emissions.

Purpose of the Study:

• To investigate the impact of secondary air injection on PM mass and size distribution during biomass combustion.
• To identify optimal secondary air injection parameters for reducing harmful emissions from wood-burning cookstoves.
• To analyze the trade-offs between PM mass reduction and ultrafine particle generation.

Main Methods:

• Experimental wood-burning cookstove platform utilized for parametric testing.
• Systematic variation of secondary air injection parameters (flow rate, velocity).
• Size-resolved measurements of PM emissions collected and analyzed under different stove settings.

Main Results:

• PM emissions are highly sensitive to secondary air injection flow rate and velocity.
• Increased velocity can enhance combustion efficiency and reduce PM.
• Excessive secondary air flow can lead to flame quenching and increased particle emissions.

Conclusions:

• Secondary air injection requires careful optimization to effectively reduce PM emissions across all size ranges.
• Balancing turbulent mixing and flame quenching is crucial for minimizing harmful emissions.
• Validated cookstove designs are essential to ensure health and climate benefits from secondary air injection technology.