Types of Steam Turbines
There are two general types of steam turbine designs.
One type is called an impulse turbine. In this type of steam turbine the rotor spins due to the force, or the direct push of steam on the blades.(impulse turbine)
The other type of steam turbine is called a reaction turbine. This type of steam turbine works on the principle that the rotor spins from, as the name suggests, a reaction force rather than an impact or impulse force. The reactive force comes from the change in steam pressure energy as the steam leaves the blades. (reaction turbine)
Understanding the distinction between these two types of turbines is important, but it should not be considered an absolute distinction in real turbines: An impulse turbine uses both the force of steam and, to a lesser extent, a reactive force when the curved blades cause the steam to change direction and pressure. A reaction turbine is moved by a reactive force but, again to a lesser degree, some of the motion is caused by the impulse force of the steam hitting the blades.
Every type of steam turbine will still need an outside energy force to convert water into steam, usually this force will be nuclear power, fossil fuel power, or concentrated solar power.