How many basic types of turbines are there?

The correct answer identifies that there are two basic types of turbines: impulse turbines and reaction turbines.

Impulse turbines operate by converting the kinetic energy of a moving fluid into mechanical energy. In this type, the fluid hits the turbine blades and causes them to spin, with the pressure of the fluid remaining constant as it passes through the turbine. Pelton wheels are a classic example of impulse turbines, where water is directed through nozzles to create high-velocity jets that strike the blades.

On the other hand, reaction turbines generate energy through a combination of pressure and velocity changes in the fluid. In this case, the fluid expands as it moves through the turbine, creating low pressure behind the blades, which aids in the rotation. Francis and Kaplan turbines represent this category. They are typically used in hydroelectric power generation, where water flows through the turbine, contributing to the rotational movement in a more continuous manner than impulse turbines.

Understanding these two types provides a strong foundation for recognizing how different turbines function based on their design and the dynamics of fluid movement.