What elements compose the combustion chamber in a gas turbine engine?

The combustion chamber in a gas turbine engine is specifically designed to efficiently mix fuel with compressed air and facilitate the combustion process. This chamber needs to handle extreme temperatures and pressures while ensuring that the combustion process remains stable and efficient.

The correct answer includes several key components that are essential for proper combustion. The casing is the outer structure that contains various elements and prevents the escape of hot gases. The perforated inner liner serves to protect the casing from the high temperatures of combustion while allowing the fuel and air mixture to enter effectively. Fuel injection refers to the system that atomizes and delivers fuel into the combustion chamber, which is critical for ensuring a thorough and efficient combustion process. Ignition is the means by which the fuel-air mixture is ignited, typically performed by ignitors or sparks. Finally, drainage is important for managing any unburned fuel or residues from the combustion process, ensuring that the system operates cleanly and efficiently.

Each of these components plays a vital role in the performance and safety of the gas turbine engine's combustion process, making this selection the most accurate description of a combustion chamber's makeup.