Which cycle demonstrates a phase change from liquid to gas in power plants?

The Rankine cycle is the correct answer as it specifically represents a thermodynamic cycle utilized in power generation, particularly in steam power plants. In the Rankine cycle, the working fluid undergoes a series of processes that involve phase changes, notably transforming from liquid to vapor.

During the cycle, the working fluid (usually water) is initially in a liquid state. It is then heated in a boiler at constant pressure, which causes it to absorb heat and undergo a phase change to steam (gas). This steam then expands through a turbine, producing work. After performing work, the steam is condensed back into a liquid in a condenser and is then pumped back into the boiler to continue the cycle.

The other cycles mentioned have different characteristics. The Otto and Diesel cycles are thermodynamic cycles primarily used in internal combustion engines and rely on air-fuel mixtures rather than working fluids undergoing phase changes in a thermal cycle context. The Brayton cycle, often associated with jet engines and gas turbines, uses a compressible fluid that remains in the gas phase throughout the process, focusing on the expansion and compression of gases rather than liquids transforming into gases.

Therefore, the Rankine cycle is the one that distinctly illustrates the phase change from liquid to gas, making it essential for