Turbomachinery performance parameter: unit discharge
For a turbine operating under head H with discharge Q, express the unit discharge (i.e., the discharge referred to a head of 1 m).
Choose the correct formula.
Difficulty: Easy
Correct Answer: Q / √H
Explanation:
Given
Actual discharge through the turbine = Q.
Operating head = H.
Concept
Unit quantities are values reduced to a reference head of 1 m. For discharge, the scaling with head is proportional to √H (from continuity with velocity ∝ √H), hence:
Formula Unit discharge, Qu = Q / √H
Checks If H increases while geometry is similar, Q increases roughly with √H, so Q/√H stays about constant.
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