For low head and high discharge, the hydraulic turbine used is

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Kaplan turbine

Explanation: The Kaplan turbine is an axial flow reaction turbine specifically designed for low-head and high-discharge conditions. It utilizes adjustable runner blades that allow it to maintain high efficiency across a wide range of flow rates. Working Principle: The turbine operates on the reaction principle where water flows axially through the runner. As water passes through the adjustable blades, a pressure drop occurs, transferring kinetic and potential energy to the runner. The pitch of the blades can be adjusted dynamically based on the flow rate to maintain optimal hydraulic efficiency. Key Formulas: $N_s = \frac{N\sqrt{P}}{H^{5/4}}$ — Specific speed formula for turbine classification; $Q = A \cdot v$ — Discharge continuity equation Key Points: Kaplan turbine is an axial flow reaction turbine.; Suitable for heads below 30 meters.; High specific speed allows for large volume handling.; Features adjustable runner blades for variable load efficiency. Advantages: High efficiency at partial loads.; Compact design for low-head sites.; Capable of handling very high flow rates. Disadvantages: Complex design due to moving runner blades.; Prone to cavitation at high velocities.; Not suitable for high-head applications. Applications: Run-of-river power plants.; Low-head hydroelectric irrigation projects. Additional Info: Kaplan turbine is a propeller-type turbine with adjustable blades.. Francis turbine is used for medium heads (30-300m).. Pelton wheel is an impulse turbine used for high heads (>300m). Answer: A is correct — The Kaplan turbine is specifically engineered for low-head and high-discharge hydraulic conditions. Exam Tip: Remember the hierarchy of head: Pelton (High), Francis (Medium), Kaplan (Low). Specific speed increases as head decreases.

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