How does a boiler stack contribute to combustion efficiency?

A boiler stack plays a crucial role in combustion efficiency primarily by exhausting flue gases outside and creating a draft. The stack's design allows for the effective removal of combustion by-products, which is essential for maintaining optimal combustion conditions within the boiler.

When the flue gases are efficiently vented through the stack, it helps to maintain the necessary negative pressure (draft) in the combustion chamber. This negative pressure facilitates the proper airflow needed for the combustion process, ensuring that the fuel burns completely. Efficient removal of these gases also prevents the build-up of unburned fuel and other by-products, which can negatively affect combustion efficiency and overall boiler performance.

In summary, the stack is integral to maintaining draft and allowing for the continuous flow of air into the combustion zone, which ultimately contributes to achieving higher combustion efficiency. This makes it clear why this aspect of the stack's function is vital in power engineering and boiler operation.