A gas turbine compressor:

• A. Always an Axial Compressor
• B. Can Be Driven by the Load Turbine
• C. Must Be Intercooled
• D. Must Be a Multi-Stage Compressor

Answer: (B)

Think about how a gas turbine uses energy to compress air and then use that compressed air to generate power. In many designs there are separate turbine stages that can provide the mechanical drive: the portion that actually compresses air is driven by a turbine, and in some configurations there is an additional power or load turbine that drives a generator or other load. Because of how these stages can be connected—sometimes on the same shaft, sometimes on different shafts with gear links—the compressor can, in some arrangements, be driven by the load turbine as well as by the main gas-generator turbine. That flexibility is why the statement is true: the compressor can be driven by the load turbine in certain designs.

The other statements aren’t universally true. A gas turbine compressor is not required to be axial; centrifugal (radial) compressors are common. Intercooling is not mandatory for all systems. And a compressor does not have to be multi-stage; some small or simple designs use a single-stage compressor.