FAA Powerplant Written Practice Test

What part of a turbine engine affects the pressure and velocity of incoming air?

1. Compressor blades

2. Diffuser section

3. Nozzle area

4. Fuel injectors

The correct answer is: Compressor blades

The compressor blades in a turbine engine are crucial for affecting the pressure and velocity of incoming air. As air enters the engine, the compressor blades rotate at high speeds, creating a pressure differential. This rotation compresses the incoming air, increasing its pressure and temperature, which is essential for efficient engine operation. In addition to increasing the pressure, the design of the compressor blades also plays a key role in controlling the velocity of the air. The shape and angle of the blades are engineered to maintain optimal airflow characteristics, allowing for smoother transitions and efficient compression. While the diffuser section, nozzle area, and fuel injectors each have important functions within the engine, they do not primarily serve the purpose of directly compressing or adjusting the pressure and velocity of incoming air like the compressor blades do. The diffuser section tends to slow down the airflow and further increase pressure after the compressor stage, and the nozzle area focuses on expanding the exhaust gases to produce thrust. Fuel injectors are responsible for introducing fuel into the airflow but do not influence the air's pressure or velocity directly. Thus, the compressor blades are the key component in this aspect of turbine engine operation.