Reheat factor definition in multi-stage turbines Select the correct definition of the reheat factor (RHF) in terms of heat drops. Choose the correct option.
Mechanical Engineering
Steam Nozzles and Turbines
Difficulty: Medium
Choose an option
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ARatio of cumulative heat drop to the isentropic heat drop
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BRatio of isentropic heat drop to the heat supplied
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CRatio of total useful heat drop to total isentropic heat drop
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DNone of the above
Answer
Correct Answer: Ratio of cumulative heat drop to the isentropic heat drop
Explanation
ConceptReheat factor (RHF) accounts for the fact that in multi-stage turbines with reheating/expansion, the sum of actual stage heat drops is slightly greater than the overall isentropic heat drop between inlet and exhaust conditions.
DefinitionRHF = (Cumulative (actual or isentropic stage) heat drop) / (Overall isentropic heat drop)
ImplicationRHF is typically slightly above 1 for practical turbines.
Final AnswerRatio of cumulative heat drop to the isentropic heat drop