How many basic types of inlet ducts are there in gas turbine engines?

In gas turbine engines, there are two basic types of inlet ducts: the subsonic inlet and the supersonic inlet.

Subsonic inlets are primarily designed to efficiently capture and direct incoming airflow at speeds below the speed of sound. These inlets are commonly used in most commercial and military jet engines where flight speeds are generally below Mach 1. The design ensures that the air enters smoothly, preventing turbulence that could reduce performance.

On the other hand, supersonic inlets are designed for high-speed applications, such as those found in supersonic aircraft. These inlets compress the incoming air to subsonic speeds before it enters the engine, which is essential for maintaining optimal engine performance and preventing shock waves that could adversely affect airflow and engine efficiency.

Understanding the distinction and functions of these two types of inlet ducts is critical for the design and operation of different types of gas turbine engines, influencing their overall performance based on the intended application.