Which type of blading results in a decrease in steam pressure and velocity due to energy transfer?

Which type of blading results in a decrease in steam pressure and velocity due to energy transfer?

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

Answer: (C)

In this context, the way energy is transferred from steam to the rotor shows up in how pressure and velocity change across the blade passage. In reaction blading, the steam expands as it flows through the moving blades, so there is a pressure drop across the blade rows and the steam gives up enthalpy to the rotor. That energy transfer manifests as a decrease in both steam pressure and its velocity as it passes through the stage. The moving blades experience a thrust from the higher-pressure steam, producing work on the rotor in a way that directly couples pressure drop with energy extraction. By contrast, impulse blading achieves most of the pressure drop in stationary nozzles before the rotor, and the rotor mainly deflects the steam to impart momentum, with less of a pressure change across the blade itself. Mixed blading combines features, but the described simultaneous drop in both pressure and velocity across the blade due to energy transfer is the hallmark of reaction blading.

In this context, the way energy is transferred from steam to the rotor shows up in how pressure and velocity change across the blade passage. In reaction blading, the steam expands as it flows through the moving blades, so there is a pressure drop across the blade rows and the steam gives up enthalpy to the rotor. That energy transfer manifests as a decrease in both steam pressure and its velocity as it passes through the stage. The moving blades experience a thrust from the higher-pressure steam, producing work on the rotor in a way that directly couples pressure drop with energy extraction.

By contrast, impulse blading achieves most of the pressure drop in stationary nozzles before the rotor, and the rotor mainly deflects the steam to impart momentum, with less of a pressure change across the blade itself. Mixed blading combines features, but the described simultaneous drop in both pressure and velocity across the blade due to energy transfer is the hallmark of reaction blading.