Which openings control the flow of secondary air into a combustion chamber?

The correct choice highlights the role of the air inlet and flue outlet in regulating the flow of secondary air into the combustion chamber. In combustion processes, secondary air is critical as it allows for the complete combustion of fuel, which enhances efficiency and reduces emissions.

The air inlet is designed to introduce fresh air into the chamber, providing the oxygen necessary for combustion. Proper airflow through the inlet ensures that there is adequate oxygen available for the fuel during the burning process.

The flue outlet, on the other hand, is primarily responsible for expelling the combustion gases produced during this process. However, it can also indirectly influence how secondary air enters the chamber. By creating a negative pressure in the flue, it can encourage more air to flow in through the air inlet, facilitating optimal combustion conditions.

In contrast, the other options do not accurately represent the mechanisms that control secondary air flow. The gas inlet and air outlet focus primarily on the introduction of fuel and exhaust of products, while the air inlet and exhaust outlet mention air and exhaust but do not specify their roles correctly within the context of secondary air. Similarly, the combustion inlet and air outlet misplace the focus on air flow logic relevant to the process.

Thus, the combination of the air inlet