In impulse turbines, blades or _____ form the rotor flow passages?

In impulse turbines, the rotor flow passages are formed by blades that are commonly referred to as "buckets." This term describes the shape and function of the turbine blades that capture the kinetic energy of a jet of water or steam. When the fluid strikes these buckets, it causes the rotor to spin, converting the fluid's energy into mechanical energy.

Using the term "buckets" specifically highlights the design and operational principle of impulse turbines. The buckets are typically designed to maximize the impact of the incoming fluid, allowing for efficient energy transfer. This design facilitates the conversion of high-velocity fluid into rotational movement, a critical aspect of impulse turbine functionality.

The other terms like "rotors," "vanes," and "scoops" may refer to components found in other types of turbines or mechanical systems but do not accurately describe the specific design elements utilized in impulse turbines. Thus, "buckets" is the appropriate terminology in this context, as it captures both the structural and functional characteristics of the turbine blades that are integral to the operation of impulse turbines.