What is a common feature of both impulse and reaction turbines?

Impulse and reaction turbines share the principle of operation based on steam expansion, which is fundamental to their design and function. Both types of turbines utilize the expansion of steam to convert thermal energy into mechanical energy.

In impulse turbines, steam is directed at high speed onto the blades, causing them to rotate. The kinetic energy of the steam is converted to mechanical energy without the steam experiencing a pressure drop across the blades; rather, it expands and impacts the blades.

In reaction turbines, steam flows through the blades, causing a pressure drop as it expands, which contributes to the rotor's motion. This means that both types utilize steam's expansion for energy conversion, albeit through different mechanisms.

Thus, the essence of both impulse and reaction turbines is that they rely on the principle of utilizing steam expansion to produce rotational movement, making it a common characteristic in their operation.