Moving blading where the space between blades is smaller at the exhaust than at the inlet and energy transfer results in a decrease in steam pressure and velocity is called what?

• A. Impulse Blading
• B. Mixed Blading
• C. Reaction Blading
• D. Radial Blading

Answer: (C)

The idea being tested is reaction blading. In a reaction stage, the moving blades form converging passages—the space between blades is smaller at the exhaust than at the inlet. As steam flows through these blade channels, it expands and transfers energy to the blades across the blade itself, which is why you see a drop in static pressure along the blade and a change in velocity relative to the blade. This contrasts with impulse blading, where energy transfer happens mainly in stationary nozzles before the blades and the blade spacing stays effectively the same, so the pressure drop across the moving blades is not the primary mechanism. Mixed blading would combine features of both, and radial blading refers to a different blade geometry and flow direction.