What does the engine diffuser do regarding static pressure and velocity?

The function of an engine diffuser is crucial in the operation of jet engines, particularly in managing airflow as it moves through various engine components. As air enters the diffuser, its velocity decreases while the static pressure increases. This is essential because it allows the airflow to spread out and become more uniform before it enters the combustion chamber.

In essence, the diffuser expands in cross-sectional area, leading to a conversion of kinetic energy (velocity) into potential energy (pressure). This process is vital for efficient engine operation, ensuring that the air entering the combustion section is at the right pressure for optimal mixing with fuel and complete combustion.

The other options highlighting increases in velocity or roles switching based on engine temperature do not accurately represent the primary function of an engine diffuser. The key function is the reduction of velocity, which results in an increase in static pressure, supporting efficient engine performance.