What type of cycle is typically used in steam turbines?

The Rankine cycle is the correct choice for steam turbines because it specifically describes the thermodynamic process where heat is added to water, causing it to turn into steam, which then expands and drives a turbine to generate mechanical work. In this cycle, the working fluid (water/steam) goes through four key processes: heating at constant pressure to convert water into steam, expanding through the turbine where it does work, condensing back to water in a condenser, and then being pumped back to the boiler at a higher pressure.

This cycle effectively utilizes the phase change of water from liquid to vapor and back, which is a critical aspect of steam turbines' operation. The Rankine cycle is highly efficient for converting thermal energy into mechanical energy, making it the standard thermodynamic cycle in power generation systems that utilize steam.

Other options, such as the Brayton cycle, involve gas turbines and do not pertain to the use of steam, while the Reversed Carnot cycle is more of a theoretical model rather than a practical cycle used in industrial applications. The term "Steam Expansion Cycle" might relate to the concepts of turbines but lacks the specificity and structure that the Rankine cycle provides in the context of steam turbine operation.