In an impulse turbine, what happens to steam as it passes through the stationary nozzle?

In an impulse turbine, as steam passes through the stationary nozzle, it is subjected to a conversion of pressure energy into kinetic energy. The design of the nozzle allows the steam to accelerate, resulting in the formation of a high-speed jet. This high-speed jet then impacts the turbine blades, causing them to rotate and thus generating work.

The transformation of energy in the nozzle is critical; while the pressure of the steam decreases as it exits the nozzle, its velocity significantly increases. This increase in velocity is due to the fact that the steam is directed into a narrow opening, which accelerates it to high speeds, thus producing a jet that can perform work on the turbine blades effectively.

Other options do not accurately describe the process occurring in an impulse turbine. For instance, the pressure does not remain constant, nor does the steam become fully condensed or experience an increase in pressure while its temperature decreases. Understanding this high-speed jet is essential for grasping the operational principles of impulse turbines in steam engineering.