Purpose of Turbines and Types

Turbines are used to convert the energy from a fluid (liquid or gas) into mechanical energy. They are widely used in various industries, including power generation, hydroelectric plants, and propulsion systems. There are several types of turbines available, each designed for specific applications and operating conditions. Some of the commonly used turbines include Pelton turbines, steam turbines, Francis turbines, and Kaplan turbines.

Explanation of Blades in Turbines

Blades play a crucial role in the functioning of a turbine. They are designed to capture the energy from the fluid flow and transfer it to the rotor, generating rotational motion. The number of blades in a turbine can vary depending on factors such as the type of turbine, design requirements, and operating conditions. In general, turbines with a higher number of blades tend to have better efficiency but can also experience increased drag and flow losses.

Comparison of Turbine Types

Let's analyze each turbine type mentioned in the options and determine which one is likely to have the lowest number of blades:

1. Pelton turbine: Pelton turbines are commonly used in hydroelectric power plants for high head applications. They are designed to operate with high water pressure and low flow rates. Pelton turbines typically have a small number of blades, usually ranging from 2 to 6. The relatively low number of blades allows for efficient energy transfer from the high-velocity water jet to the rotor.

2. Steam turbine: Steam turbines are widely used in power generation plants, where steam is generated by burning fossil fuels or using nuclear energy. Steam turbines can have a varying number of blades depending on their design and size. Large steam turbines used in power plants can have hundreds of blades, while smaller turbines used in industrial applications may have fewer blades.

3. Francis turbine: Francis turbines are commonly used in hydroelectric power plants for medium head applications. They are designed to operate with a wide range of flow rates and water pressures. Francis turbines typically have a moderate number of blades, ranging from 8 to 24. The number of blades can be adjusted to optimize the turbine's performance under specific operating conditions.

4. Kaplan turbine: Kaplan turbines are mainly used in hydroelectric power plants for low head applications. They are designed to operate with low water pressures and high flow rates. Kaplan turbines typically have a relatively high number of blades, ranging from 3 to 8. The higher number of blades allows for efficient energy capture from the flowing water.

Conclusion

Based on the above analysis, the turbine with the lowest number of blades among the given options is the Kaplan turbine. Kaplan turbines are known for having a relatively high number of blades compared to other turbine types.