Short Answer:

In hydraulic turbines, energy is transferred from flowing water to the turbine blades. The moving water contains potential and kinetic energy, which strikes the blades and causes the turbine shaft to rotate. This mechanical rotation is then used to generate electricity.

The process works by converting the energy of water into mechanical energy through the design of turbine blades, casing, and nozzles. Depending on the turbine type (like Pelton, Francis, or Kaplan), energy transfer occurs by impact, reaction, or a combination of both, ensuring efficient power generation in hydroelectric plants.

Detailed Explanation:

Energy Transfer in Hydraulic Turbines

Hydraulic turbines are machines that convert the energy of flowing or falling water into mechanical energy. This mechanical energy is then converted into electrical energy using a generator. The process of energy transfer in hydraulic turbines depends on the type of turbine and the nature of water flow—whether it is high-head, medium-head, or low-head.

The water entering a turbine contains two forms of energy:

1. Potential Energy – due to its height or head.
2. Kinetic Energy – due to its velocity.

The goal of the turbine is to absorb as much of this energy as possible and convert it into rotational motion of the shaft.

1. Transfer by Impact (Impulse Turbines)
   In impulse turbines like the Pelton turbine, energy transfer takes place mainly through the impact of high-velocity water jets.

• Water is directed through a nozzle and strikes the turbine buckets.
• Only kinetic energy is used; pressure remains constant.
• The force of the water jet causes the wheel to spin, transferring energy.
• These are suitable for high-head and low-flow conditions.

In this method, energy is transferred in the form of force created by the water jet hitting the curved blades, causing rotation.

2. Transfer by Reaction (Reaction Turbines)
   In turbines like Francis and Kaplan turbines, energy transfer happens due to both pressure and velocity changes.

• Water enters under pressure and flows over moving blades.
• Both kinetic and pressure energy are converted into mechanical energy.
• The flow is continuous, and the entire passage is filled with water.
• Suitable for medium to low head and large flow conditions.

Reaction turbines are designed in such a way that water exerts pressure and pushes the blades as it flows through them, smoothly transferring energy to the rotor.

3. Conversion to Mechanical and Electrical Energy
   The turbine shaft rotates due to energy transfer from water. This shaft is connected to a generator.

• The mechanical rotation spins magnets inside the generator.
• This produces electrical energy through electromagnetic induction.
• The electricity is then transferred to the grid for distribution.

Thus, hydraulic turbines serve as a link between natural water flow and electrical power systems.

4. Factors Affecting Energy Transfer Efficiency
   Several factors influence how efficiently energy is transferred:

• Blade shape and angle
• Turbine design (axial, radial, mixed flow)
• Head and flow rate of water
• Proper alignment and smooth operation
• Absence of cavitation and friction losses

Engineers aim to design turbines in such a way that maximum water energy is captured and converted with minimal losses.

Conclusion

Energy transfer in hydraulic turbines occurs when the energy of water (potential and kinetic) is converted into mechanical energy by rotating blades. This rotation drives a generator to produce electricity. Depending on turbine type, energy is transferred either by impact or reaction. Hydraulic turbines are key to efficient hydroelectric power generation.