What does the compression ratio of a gas turbine engine measure?

The compression ratio of a gas turbine engine is an important metric that measures how much the air is compressed before it enters the combustion chamber. It is defined as the ratio of the volume of air in the combustion chamber when the piston is at the bottom of its stroke to the volume of air in the chamber when the piston is at the top of its stroke.

A higher compression ratio indicates that the engine is compressing the intake air more, which typically leads to increased pressure and temperature of the air entering the combustion chamber. This enhances the efficiency and performance of the engine by allowing for more efficient combustion of fuel, leading to better thrust and overall performance.

Understanding the compression ratio is vital because it directly influences the engine's efficiency, power output, and fuel consumption characteristics. In contrast, the other options focus on different aspects of engine performance, such as rotational speed, fuel consumption rates, or thrust output, which do not directly pertain to how air is compressed within the engine. Recognizing the significance of the compression ratio is key to understanding turbine engine functionality and optimization in aviation.