Turgo Turbine was developed Gilkes Energy Company in 1919. The design of this impulse water turbine is inspired from Pelton turbine. The working principle of this turbine is same as other impulse water turbines. It converts the kinetic energy from the water jet into mechanical energy.
The main difference between the Turgo and Pelton turbine is the design of runner buckets. The runner of Turgo turbine is the half slice of Pelton turbine. The runner buckets of Pelton turbine has two curved structures as shown in the figure 1 but the Turgo bucket is the half slice of the Pelton bucket as shown in the figure 2.
Figure 1: Bucket of the runner of Pelton turbine
Figure 2: Buckets of the runner of Turgo turbine
Turgo turbine can handle faster water jet effectively due to its unique bucket design. Buckets in the Pelton turbine don’t remove water quickly therefore, water in the bucket interferes with the incoming jet and also reduces the efficiency of the turbine. On the other hand buckets in Turgo turbine remove water from runner quickly.
The angel of water jet also plays an important role in this regard. Usually, water jet hits the runner at the angle of 20 degrees. Water jet at this angle provides the maximum impulse to the runner and let the water exit from the other side of the bucket without interfering with incoming water. The working scheme of the Turgo turbine is shown in figure 3.
Figure 3: The working scheme of Turgo turbine
The material of bucket, the diameter of the runner, the width of the nozzle, and height of the head decide the overall effectiveness and efficiency of this turbine. Usually, speed increasing transmission is used with turbines to operate generator at higher speed but Turgo turbine can be connected directly to the generator due to its faster runner. In lab tests, the efficiency of Turgo turbine can be up to 90% but in hydropower plants its efficiency is about 87%.
Though the efficiency of Turgo turbine is usually less than that of Pelton turbine but it provides a cost-effective way to generate electricity from medium and small heads and works in the heads of 15 meters to 300 meters. The main reason for less efficiency of Turgo turbine is its less sturdy runner vanes/buckets. Turgo turbine is usually installed in the head where Pelton turbine and Francis turbine overlap. Since Turgo runner is the half slice of Pelton turbine, therefore, Turgo turbine produces the same power as that of Pelton turbine if it has twice the diameter as that Pelton runner.
Large diameter leads to higher rotational speed. In some cases, Turgo turbine can even provide better efficiency than Pelton turbine due to its ability to handle the faster flow of water. Turgo turbine can be installed at any site where the Pelton turbine can be used but Pelton turbine can’t be used in all applicable sites of Turgo turbines. All these applications of Turgo turbine make it highly desirable for generating electricity.
