What is the primary factor that controls the pressure ratio of an axial-flow compressor?

What is the primary factor that controls the pressure ratio of an axial-flow compressor?

• A. Compressor Inlet Temperature
• B. Engine RPM
• C. Number of Stages in Compressor
• D. Compressor Inlet Pressure

Answer: (C)

In an axial-flow compressor, the air gains pressure as it passes through each stage, and the overall pressure rise is the product of the rises from all stages. So the total pressure ratio you can achieve scales with how many stages the compressor has—more stages mean more opportunities to raise pressure, assuming the stages are designed to work together at the operating point. Inlet temperature, engine RPM, and inlet pressure influence how effectively those stages perform at a given point, but they don’t set the maximum pressure ratio the compressor can reach. Therefore, the number of stages in the compressor is the main factor that controls the pressure ratio.

In an axial-flow compressor, the air gains pressure as it passes through each stage, and the overall pressure rise is the product of the rises from all stages. So the total pressure ratio you can achieve scales with how many stages the compressor has—more stages mean more opportunities to raise pressure, assuming the stages are designed to work together at the operating point. Inlet temperature, engine RPM, and inlet pressure influence how effectively those stages perform at a given point, but they don’t set the maximum pressure ratio the compressor can reach. Therefore, the number of stages in the compressor is the main factor that controls the pressure ratio.