Degree of reaction from enthalpy drops in a turbine stage Given: Isentropic enthalpy drop in the moving blade (rotor) is two-thirds of the isentropic enthalpy drop in the fixed blade (stator). Compute the degree of reaction R = (rotor drop)/(stator drop + rotor drop). Choose the correct value.
Mechanical Engineering
Steam Nozzles and Turbines
Difficulty: Medium
Choose an option
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A0.40
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B0.56
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C0.67
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D1.67
Answer
Correct Answer: 0.40
Explanation
Given data
- Let Δhf = isentropic drop in fixed blades (stator).
- Δhm (moving/rotor) = (2/3) Δhf.
Step-by-Step calculationTotal stage drop = Δhf + Δhm = Δhf + (2/3)Δhf = (5/3)Δhf.R = Δhm / (Δhf + Δhm) = ( (2/3)Δhf ) / ( (5/3)Δhf ) = 2/5 = 0.40.
Final Answer0.40