Francis and Kaplan Turbines

Introduction

The Francis turbine is mostly a preferred hydraulic turbine. In the year 1855 Francis turbine was invented and developed by James B. In the year 1913 Kaplan turbine was invented and developed by Viktor Kaplan who is an Austrian professor. To achieve control over a wide range of flow and water levels combining automatically adjusted wicket gates with automatically adjusted airscrew blades.

Francis Turbine

The Francis turbine is mostly a preferred hydraulic turbine. In the year 1855 Francis turbine was invented and developed by James B. Francis. In Francis, turbine water leaves axially at its center and enters radially at its outer periphery. It is a mixed hydraulic turbine.

Advantages of a Francis Turbine

Some advantages of a Francis turbine are as follows:

• In comparison to other types of turbines, the corridor size is small in the Francis turbine.
• Also in comparison to other types of turbines, it has a lower maintenance cost

Disadvantages of a Francis Turbine

Some disadvantages of a Francis turbine are as follows:

• Working with a height greater than 800 m causes a problem for the Francis turbine.
• It has a problem with cavitation.
• The turbine may face the problem by the entry of water with dust particles.

Main components of Francis turbine

The main components of the Francis turbine are as follows:

• Speed Ring
• Draft Tube
• Tailrace
• Runner
• Scroll Casing
• Guide Vanes

Kaplan Turbine

In the year 1913 Kaplan turbine was invented and developed by Viktor Kaplan who is an Austrian professor. To achieve control over a wide range of flow and water levels combining automatically adjusted wicket gates with automatically adjusted airscrew blades. A Kaplan turbine is special in its way, i.e. to preserve maximum efficiency of water flow rates, the blade can change its demand accordingly. The axial flow in Kaplan turbines is that the water flows from both in and out of Kaplan turbines through the rotational axis. A turbine must be designed in such a way that a large amount of water can flow through it without causing any damage. A Kaplan turbine is having some rotor blade (the turbine’s blades are not flat, blade’s exterior portion moves more smoothly than the interior portion, so the rotation of the blades in the Kaplan turbine is slight) that directly connects to the central shaft of the turbine and to adjust the angles, the blades are attached with adjustable joints. A Kaplan turbine is the type of turbine that evolved from the Francis Turbine, unlike the Francis Turbine, the Kaplan turbine has the capacity of working at a high flow rate and low head. The Kaplan turbine is a propeller-type water turbine.

Advantages of the Kaplan Turbine.

Some advantages of a Kaplan Turbine are as follows –

• As compared to other turbines, the Kaplan turbine is small in size so it consumes less space.
• The construction of the Kaplan turbine is more feasible.
• The Kaplan turbine is the type of turbine that has more efficiency than other types of hydraulic turbines.

Disadvantages of a Kaplan Turbine.

Some disadvantages of a Kaplan Turbine are as follows –

• The main disadvantage of the Kaplan turbine is the cavitation problem; this problem can be solved if the stainless steel is used for runner blades.
• This operation requires a large flow of water.
• The shaft is only placed vertically.

Main Components of Kaplan Turbine

  The main components of Kaplan Turbines are:

• Guide  Vane Mechanism
• Runner Blades
• Draft Tube

There are again four types of Draft Tube –

• Moody Spreading Draft Tube
• Elbow with the Varying Cross-section
• Simple Elbow Draft Tube
• Conical Diffuser or Divergent Draft Tube

• Scroll Casing

Application of Kaplan Turbine

There are several applications of Kaplan Turbine are –

• To produce electric power Kaplan turbines are largely used everywhere around the world.
• Kaplan turbines are not money friendly but they have been running for decades.
• Kaplan turbines can be individually designed for any site to operate at more than 90% highest potential efficiency.

Conclusion

This is to conclude that the Francis turbine is a mixed hydraulic turbine and the Kaplan turbine is an axial flow reaction turbine. . In the year 1855 Francis turbine was invented and developed by James B and in the year 1913 Kaplan turbine was invented and developed by Viktor Kaplan who is an Austrian professor