What is Rateau impulse turbine described as?

• A. A series of Curtis impulse turbines
• B. A single-stage nozzle turbine
• C. A cross-flow turbine
• D. A series of reaction turbines

Answer: (A)

Rateau impulse turbine is built as a sequence of impulse stages, effectively a chain of Curtis impulse turbines connected in series. Each stage has fixed nozzles that convert steam pressure drop into a high-velocity jet, which transfers momentum to moving blades. The steam then passes to the next stage for further energy extraction, continuing this series through multiple nozzle–blade pairs. This staged impulse arrangement achieves higher total energy extraction than a single-stage impulse setup and is distinct from reaction or cross-flow designs, which rely on pressure changes in the blades themselves rather than jet momentum transfer.