Question

Choose the correct statement with respect to the impulse steam turbine operated based on Rankine cycle

• A. Complete conversion of pressure into velocity initially in the nozzles
• B. Conversion of pressure into kinetic energy in fixed blades and expansion in moving blades
• C. Requirement of draft tube is necessary
• D. Degree of reaction is high

Hint:

In impulse steam turbines, the steam's pressure is converted into velocity in the nozzles, and the turbine blades extract energy from the high-velocity steam.

Answer 1

The Correct Option is A

Step 1: Impulse steam turbine operation
In an impulse steam turbine, the pressure of steam is converted into velocity in the nozzles. The steam expands through the nozzles, increasing its velocity. The blades of the turbine then convert this kinetic energy into mechanical work. Therefore, Option (1) is correct.
Step 2: Option Analysis
Option (2): The conversion of pressure into kinetic energy happens in the nozzles, not the fixed blades. Fixed blades only direct the steam flow, while moving blades extract energy.
Option (3): A draft tube is not necessary for impulse turbines; it is more relevant to reaction turbines.
Option (4): The degree of reaction is low in impulse turbines, as most of the energy is converted in the nozzles. Conclusion
The correct answer is Option (1) because the primary function of the nozzles in an impulse turbine is to convert steam pressure into velocity.