What Is Meant By Compounding Of Turbine? Types, Advantages of Compounding

🔗What is Turbine? Basic working principle of turbine

 

What is compounding of turbine? The necessity of compounding

In a simple turbine the energy of steam/ water extracted in single stage. The main problem with the single stage operation is that the large portion of energy of may get lose due to higher exit velocity and pressure. This loss is known as carry over loss/ leaving loss. In other situation. The one stage operation cause an extremely high speed of rotor which cause design complication due to high vibrations. Which eventually leads the damage of structure. In order to avoid these drawbacks and reduce the speed of rotor, the energy of fluid extracted in number of stages (in multiple stages) rather than a single stage. This method is known as compounding of turbine.

Sets of blades and nozzle are arranged in such a way that the pressure energy and kinetic energy are absorbed in stages as the working fluid flow over the blades. The multiple rotor is then keyed to common shaft.

Types of compounding of turbine. Velocity compounding and pressure compounding

According the arrangement and of blades and nozzle, and the way the energy extracted, the compounding is divided into

Velocity compounding: Kinetic energy (velocity) of Working fluid (steam) is extracted, and convert it to useful work in multiple stages. The pressure drop (steam expand) occurs at first nozzle only.

Pressure compounding: Steam expansion (pressure drop) occur in multiple stages.

Pressure-velocity compounding: it is a combination of both velocity compounding and pressure compounding. Both velocity and pressure energy extracted in multiple stages.

Reaction turbine: Reaction turbine also a type of pressure compounding.

The types of compounding to adopt for will depend upon the specific needs and application.

Advantages of compounding of turbine

• Compounding reduces the speed of the rotor. If the same energy extracted by the single stage the speed of rotor will too high to practical use.
• Minimize the vibration and noises.
• The turbine compounded for high efficiency with reasonable speed, dimensions.
• The compounding of turbine helps to design the turbine of proper size.
• Reduce the wastage of steam and energy loss due to carry over loss (by the high exit velocity of fluid)