Where is the highest pressure found in a turbojet engine?

• A. Combustor
• B. Turbine last stage
• C. Impeller to diffuser
• D. Inlet lip

Answer: (C)

The air is pressurized most where the compressor does its work. As it passes through the last impeller, the air reaches its highest total pressure right at the compressor discharge, just before the diffuser. The diffuser then slows the flow and converts some of that velocity into static pressure, but the peak pressure is set by the compressor discharge. After that, pressure drops through the combustor and turbine due to energy extraction and expansion, and the inlet lip only experiences a modest ram rise.