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.
Mechanical Engineering
Hydraulic Machines
Difficulty: Easy
Choose an option
-
AQ · √H
-
BQ / H
-
CQ / √H
-
DQ / H^(3/2)
Answer
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:FormulaUnit discharge, Qu = Q / √H
ChecksIf H increases while geometry is similar, Q increases roughly with √H, so Q/√H stays about constant.
Final AnswerQ / √H.