Impulse Turbine and Reaction Turbine
Turbine: A turbine is a rotary mechanical device that extracts energy from a fluid flow and converts it into useful work. In a turbine, fluid energy is transformed into mechanical energy. Unlike pumps, where mechanical energy is converted into fluid energy, turbines operate in the reverse manner. They are among the most cost-effective methods of producing electricity.
Turbines can be classified into two main types based on the type of hydraulic action or energy at the inlet:
- Impulse Turbine
- Reaction Turbine
Impulse Turbine
An impulse turbine operates by the impulsive force of fluid, which causes the turbine wheel to rotate. The fluid flow is tangential to the runner, and all the energy at the entrance is in the form of kinetic energy. Key characteristics of impulse turbines include:
- High Head Required: Impulse turbines require a high head (H > 250m) to function effectively.
- Low Flow Rate: These turbines operate with a low flow rate, making them suitable for high-head, low-flow applications.
- Low Specific Speed: The specific speed of an impulse turbine typically ranges from 10 to 35.
- Example: The Pelton turbine is a well-known type of impulse turbine.
Impulse Turbine Reaction Turbine
A reaction turbine, on the other hand, develops torque by reacting to the pressure of a fluid. The fluid flow is axial to the runner, and the energy at the entrance is a combination of kinetic energy and pressure. Key characteristics of reaction turbines include:
- Low Head Required: Reaction turbines operate effectively with a low head (H < 60m).
- High Flow Rate: These turbines are designed to handle a high flow rate, making them suitable for low-head, high-flow applications.
- High Specific Speed: The specific speed of a reaction turbine typically ranges from 300 to 1000.
- Example: The Kaplan turbine is a well-known type of reaction turbine.
Reaction Turbine Conclusion
Understanding the difference between impulse and reaction turbines is crucial for selecting the right turbine for specific applications. Impulse turbines are ideal for high-head, low-flow situations, where kinetic energy drives the turbine. In contrast, reaction turbines are suited for low-head, high-flow scenarios, where both pressure and kinetic energy contribute to turbine operation.
