What is the primary function of a draft fan in a combustion system?

The primary function of a draft fan in a combustion system is to create the necessary airflow for combustion. Draft fans facilitate the movement of air into the combustion chamber, ensuring that there is an adequate supply of oxygen to support the combustion process. This airflow is crucial for proper fuel ignition and efficient burning, which in turn leads to optimized energy output and reduced emissions.

When air enters the combustion chamber, it combines with fuel, allowing for a controlled burn. An insufficient airflow can lead to incomplete combustion, resulting in a buildup of harmful gases and reduced system efficiency. Therefore, the draft fan is essential for maintaining the correct balance of air and fuel, which is fundamental for achieving safe and efficient operation of the combustion system.

The other options do not directly represent the primary purpose of a draft fan. While removing smoke, cooling components, and recirculating exhaust gases are all important aspects of combustion systems, they are not the main role of the draft fan itself. The correct answer highlights the essential function of ensuring adequate airflow, which is critical for achieving a successful combustion process.