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Examoogle • User • info@examoogle.com • EE-2024-8821
Chapter 1 of 12 • Page 1 of 248🔒 Protected PDF • Watermarked
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The runner of __________ turbine always be under pressure of above atmospheric pressure.
Turgo
Girand
Kaplan
None of the mentioned
Kaplan
The Kaplan turbine is a reaction turbine where the fluid enters the runner at a pressure significantly higher than atmospheric pressure. This pressure difference is maintained throughout the flow passage to facilitate energy extraction as the water moves across the runner blades.
The Kaplan turbine is a reaction turbine where the fluid enters the runner at a pressure significantly higher than atmospheric pressure. This pressure difference is maintained throughout the flow passage to facilitate energy extraction as the water moves across the runner blades.
Pinlet>Patm — Inlet pressure is always maintained above atmospheric in reaction turbines
ηh=PwaterPrunner — Hydraulic efficiency definition
In a reaction turbine like the Kaplan, the pressure drop occurs partially in the fixed guide vanes and partially in the moving runner blades. The runner is completely enclosed in a casing, and the water flows under high pressure, ensuring the blades are fully submerged and subjected to a pressure greater than the ambient atmospheric pressure throughout the energy conversion process.
Kaplan turbines are axial flow reaction turbines.
They are designed for low head and high discharge conditions.
The runner blades are adjustable to maintain high efficiency under variable load.
Draft tubes are mandatory to recover pressure energy.
High efficiency at part-load due to adjustable blades.
Compact size compared to other turbines for low head applications.
Complex mechanical construction.
Risk of cavitation due to reaction principle.
Low head hydro power plants.
Run-of-river projects.
The Pelton wheel is an impulse turbine where the pressure at the runner is atmospheric.
Turgo turbines are also impulse-type turbines, thus maintaining atmospheric pressure at the runner.
C is correct — The Kaplan turbine is a reaction turbine which operates with the runner fully enclosed and subjected to pressure higher than atmospheric.
Remember: Reaction turbines (Kaplan/Francis) have pressure variation across the runner, while Impulse turbines (Pelton/Turgo) maintain constant atmospheric pressure around the runner.