Steam turbine blades: definition check for blade velocity coefficient Statement to judge: “The blade velocity coefficient equals the ratio of the relative velocity of steam at the outlet tip of the blade to the relative velocity at the inlet tip of the blade.” Choose whether the statement is correct or incorrect.
Mechanical Engineering
Steam Nozzles and Turbines
Difficulty: Easy
Choose an option
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AAgree (the definition is correct)
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BDisagree (the definition is incorrect)
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CCorrect only for impulse turbines
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DCorrect only for reaction turbines
Answer
Correct Answer: Agree (the definition is correct)
Explanation
Concept/Approach
- The blade velocity coefficient (sometimes denoted by kb) models frictional loss within the moving blade passage: kb = (relative exit speed)/(relative inlet speed) = Vr2/Vr1 ≤ 1.
- This definition is general and used in stage loss models.
Final AnswerAgree — it is the ratio Vr2/Vr1.