Kaplan Turbine

what is a kaplan turbine ?

A Kaplan turbine is a type of hydroelectric turbine used to convert the energy of flowing water into mechanical energy. It is specifically designed for low-head, high-flow conditions, making it suitable for installations where there is a large volume of water available but the available head (the height difference between the water source and the turbine) is relatively low.


The Kaplan turbine was developed by the Austrian engineer Viktor Kaplan in the early 20th century. It is a propeller-type turbine that consists of a runner with adjustable blades and a spiral-shaped casing. The runner is connected to a shaft, which is in turn connected to a generator to produce electricity.

One of the key features of the Kaplan turbine is its ability to adjust the angle of the blades based on the flow conditions. This allows the turbine to operate efficiently over a wide range of flow rates and maintain a high level of performance even when the water flow varies. The adjustable blades also enable the turbine to operate at different heads, making it versatile for various hydroelectric power generation projects.

The Kaplan turbine is commonly used in run-of-the-river hydroelectric power plants, where the water is diverted from a river or a canal and then returned to the same watercourse downstream. It is also utilized in tidal power installations and other applications that involve large volumes of water with relatively low heads.

Overall, the Kaplan turbine is an efficient and adaptable technology that has played a significant role in the development of renewable energy generation from water resources. Its design allows for optimal utilization of available water resources, making it a preferred choice for hydroelectric power projects worldwide.

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kaplan turbine diagram

kaplan turbine parts

The Kaplan turbine consists of several main parts that work together to convert the energy of flowing water into mechanical energy. These parts include:

These main parts of the Kaplan turbine work in coordination to efficiently harness the energy of flowing water and generate mechanical rotation, which is then converted into electrical energy by the connected generator.

kaplan turbine working principle

The Kaplan turbine operates based on the principle of converting the kinetic energy of flowing water into mechanical energy, and subsequently, into electrical energy.

The process begins with water intake from a water source, such as a river or canal. The flow of water is controlled by adjustable guide vanes, also known as wicket gates, located at the entrance of the turbine. By changing the position of the guide vanes, the flow rate and direction of the water entering the turbine can be regulated. This adjustment optimizes the turbine’s performance under different operating conditions.

Once inside the turbine, the water flows over the runner, which consists of adjustable blades or vanes. The runner blades are attached to a rotating shaft. As the water passes through the runner, the kinetic energy of the water is transferred to the blades, causing the runner to rotate.

The rotational motion of the runner is then transmitted to a turbine shaft, which connects to a generator. The generator converts the mechanical energy from the rotating shaft into electrical energy, producing electric power. The amount of power generated depends on the flow rate and head (the height difference between the water source and the turbine).

After passing through the runner, the water exits through a draft tube. The draft tube provides a smooth transition for the water as it leaves the runner, helping to maintain a low-pressure environment at the turbine outlet. This low-pressure condition improves the turbine’s efficiency by reducing the pressure difference between the inlet and outlet, allowing more energy to be extracted from the flowing water.

Finally, the water is directed into the tail race, which is a channel or conduit that returns the water to the natural watercourse downstream of the turbine.

The operation of the Kaplan turbine can be controlled and adjusted by varying the positions of the guide vanes and runner blades. This allows for optimal performance under different flow conditions and load demands. By adjusting the angle of the guide vanes and the blades, the turbine can maintain high efficiency and adapt to changes in water flow rates and heads.

In summary, the working principle of the Kaplan turbine involves controlling the flow of water with guide vanes, directing it through the runner where kinetic energy is converted into mechanical energy, transmitting the mechanical energy to a generator, and finally, converting it into electrical energy. The adjustable blades and guide vanes enable the turbine to adapt to varying flow conditions, optimizing its performance and making it a versatile and efficient technology for hydroelectric power generation.

applications of kaplan turbine

Kaplan turbines find applications in various hydroelectric power generation projects. Some of the common applications include:

Overall, the versatility and adaptability of Kaplan turbines make them suitable for a range of hydroelectric power generation applications, particularly in low-head, high-flow conditions.

advantages of kaplan turbine

The Kaplan turbine offers several advantages, which have contributed to its widespread use in hydroelectric power generation. Some of the advantages of Kaplan turbines include:

Overall, the high efficiency, versatility, compact design, and other advantages of Kaplan turbines make them a preferred choice for many hydroelectric power projects. Their ability to adapt to varying flow rates, coupled with their durability and fish-friendly design options, contribute to their popularity in sustainable energy generation.

disadvantages of kaplan turbine

While the Kaplan turbine offers several advantages, it also has a few disadvantages that should be considered. Some of the drawbacks of Kaplan turbines include:

Despite these disadvantages, Kaplan turbines remain a popular choice for hydroelectric power generation in appropriate conditions. Ongoing advancements in design and technology aim to mitigate these drawbacks and improve the overall performance and environmental impact of Kaplan turbines.

difference between kaplan and francis turbine

Certainly! Here is a table highlighting the main differences between Kaplan and Francis turbines:

Kaplan TurbineFrancis Turbine
TypeAxial Flow TurbineMixed Flow Turbine
ApplicationLow to Medium HeadMedium to High Head
Runner DesignPropeller-like bladesCurved blades
Blade AdjustmentBlades are adjustable in pitch angleBlades are fixed and non-adjustable
EfficiencyHigher efficiency at low flow ratesHigher efficiency at high flow rates
Flow ControlPrimarily governed by the adjustable bladesPrimarily governed by the guide vanes
Operating RangeBest suited for wide flow rate variationsBest suited for a relatively narrow flow rate range
Size RangeUsually larger in sizeAvailable in a wide range of sizes
Water FlowHandles a large volume of water with low headHandles a moderate volume of water with high head
CostGenerally more cost-effective due to simpler designGenerally more expensive due to complex construction
MaintenanceRelatively easier maintenance and repairMay require more complex maintenance due to design
Application ExamplesRun-of-river, low-head hydropower installationsHigh-head hydropower plants, pumped storage applications

Please note that this table provides a general overview of the differences between Kaplan and Francis turbines. Specific design variations and advancements may result in further differentiating factors.

Reference : https://en.wikipedia.org/wiki/Kaplan_turbine

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