The Turgo turbine is an impulse-type water turbine designed for medium-head applications (typically 50–250 meters) and higher flow rates compared to the Pelton wheel. Its structure is optimized for efficient energy conversion by directing water jets at an angle across the runner blades. Below is a detailed breakdown of its key components and their functions:

1. Runner

• Description: The rotating unit with curved buckets (blades) arranged radially around a central hub.

• Function: Captures kinetic energy from high-velocity water jets. The buckets are shaped to allow water to enter one side at an angle (15–20°) and exit the opposite side, minimizing interference and enabling continuous rotation.

• Material: Typically made of stainless steel (e.g., CA6NM) for durability against erosion and cavitation.

• 2. Nozzle and Spear Valve

• 

• Nozzle: Converts pressurized water into a high-speed jet directed at the runner.

• Spear Valve: A conical needle inside the nozzle that adjusts the jet size to regulate water flow and power output without pressure loss.

• Function: Ensures precise control over the jet’s velocity and volume.

• 3. Casing

• Description: A robust enclosure surrounding the runner and nozzle.

• Function: Protects internal components, contains splashing water, and directs spent water to the tailrace. Unlike reaction turbines, it operates at atmospheric pressure.

• 

• 4. Shaft and Bearings

• Shaft: Connects the runner to the generator, transmitting mechanical energy.

• Bearings: Support the shaft, reducing friction and allowing smooth rotation. Anti-friction bearings (e.g., roller or ball bearings) are commonly used.

• 

• 5. Brake System

• Function: Safely stops the turbine during emergencies or maintenance. A mechanical brake or water deflector (to divert the jet away from the runner) is employed.

• 6. Governor

• Function: Automatically adjusts the spear valve or deflector to maintain constant rotational speed under varying loads, ensuring stability and efficiency.

• Key Design Features

• Angled Jet Interaction: Water enters buckets on one side and exits the opposite, enabling higher flow rates and a more compact runner than Pelton turbines.

• Multi-Jet Capability: Some Turgo turbines use multiple nozzles to increase power output, though single-jet designs are more common.

• Applications

• Ideal for medium-head, high-flow hydropower sites, such as mountainous regions or irrigation networks.

• Suitable for decentralized energy systems due to adaptability across a range of flow conditions.

• Comparison with Pelton Turbines

• Flow Handling: Turgo accommodates higher flow rates due to its bidirectional water exit.

• Size: Smaller runner diameter for equivalent power, offering space and cost advantages.

• Head Range: Optimal for medium heads (50–250 m), whereas Pelton excels in very high heads (>250 m).

• The Turgo turbine’s innovative bucket design and structural efficiency make it a versatile solution for sustainable hydroelectric projects, balancing performance, compactness, and operational flexibility.

• Efficiency: Slightly lower peak efficiency than Pelton wheels but performs better under variable flow conditions.

• The different between Pelton turbine and Turgo turbine

Turgo turbines are a type of impulse turbine, similar to Pelton wheels but with some differences. They use the velocity of water to generate energy, So the water is directed onto the turbine blades or buckets, and the impulse of the water causes the turbine to spin.

Turgo turbines were developed after the Pelton turbine. The main difference is the way the water jet hits the buckets. In Pelton turbines, the jet hits the buckets in the middle and splits into two, exiting on either side. But Turgo turbines have a different design where the jet hits the buckets at an angle, allowing the water to enter one side and exit the other. This might allow for higher flow rates or different head heights.

So, the structure of a Turgo turbine. First, there's the runner, which is the rotating part. The runner has buckets or blades arranged around it. These buckets are shaped to efficiently capture the water jet. Then there's the nozzle, which directs the water onto the buckets. The nozzle is important because it controls the flow and speed of the water jet. The casing would enclose the runner and direct the water flow. There's also a spear valve or some flow control mechanism to adjust the amount of water flowing through the nozzle. The shaft connects the runner to the generator, transferring the mechanical energy. Bearings would support the shaft, and there might be a brake system to stop the turbine if needed.

The buckets in Turgo turbines are different from Pelton. They are designed so that the water enters from one side and exits the opposite side. This allows the turbine to handle a larger volume of water compared to Pelton, which might make Turgo turbines suitable for medium head applications. Pelton is usually for high head, low flow, whereas Turgo can handle a bit more flow. So maybe the bucket design is key here. The angle at which the jet hits the buckets must be optimized for efficiency.

Also, the materials used would need to be strong to withstand the high-speed water jet. Stainless steel is common for the runner and buckets. The nozzle might have a spear that can move in and out to adjust the jet size, controlling the flow without losing pressure. The casing doesn't need to withstand high pressure since it's an impulse turbine; the water is at atmospheric pressure after leaving the nozzle. But it should be sturdy to protect the components and direct the water away after it exits the buckets.

Turgo turbines are used in medium head hydropower sites, typically between 50 to 250 meters. They can handle higher flow rates than Pelton wheels, which makes them suitable for certain hydroelectric projects. Their efficiency is good over a range of flow conditions, which is a plus.