In a multi-stage centrifugal compressor, which statement about the stages is correct?

• A. Each stage has identical volume to other stages
• B. Each stage operates at a higher temperature than the previous stage
• C. Each stage carries a different discharge pressure
• D. Each stage uses a different lubricant

Answer: (A)

In a multi-stage centrifugal compressor, the same gas mass flow passes through every stage in series, so each stage is designed to handle roughly the same volumetric flow. That’s why the stages are built with identical flow capacity and geometry—the machine is made from repeatable, modular stages to keep loading balanced and the overall design efficient. The pressure gain comes from stacking stages, so each stage’s discharge pressure is higher than the one before it, even though the volume the stage processes remains essentially the same. Temperature behavior depends on cooling between stages, and lubrication is typically shared across the machine rather than being unique to each stage.