What is Rankine cycle and How it work?

  Rankine cycle working principle  The mechanism by which some heat engines, such as steam turbines or reciprocating steam engines, permit m...

 

Rankine cycle working principle 

The mechanism by which some heat engines, such as steam turbines or reciprocating steam engines, permit mechanical work to be extracted from a fluid as it flows between a heat source and a heat sink is described by the Rankine cycle, an idealised thermodynamic cycle. William John Macquorn Rankine, a Scottish polymath professor at Glasgow University, is the subject of the Rankine cycle.

The Rankine cycle's physical structure

Pump, Boiler, Turbine, Condenser, and Pump

The system receives heat energy from a boiler, where the working fluid—typically water—is transformed into a high-pressure gaseous state (steam) to drive a turbine. The fluid is allowed to return to a liquid form after passing over the turbine in order to recover waste thermal energy.

For the sake of streamlining computations, friction losses are frequently ignored throughout the system because they are typically far less substantial than thermodynamic losses, especially in larger systems.

The Rankine cycle consists of four steps. In the T-s diagram, the states are denoted by numbers 

T-S Diagram for Rankine cycle 

Process 1-2 involves pumping the working fluid from low to high pressure. The fluid is now a liquid, thus the pump doesn't need much energy to operate. Compression that is isentropic is process 1-2.

Process 2-3: The high-pressure liquid enters a boiler where it is boiled to a dry saturated vapour at a constant pressure by an external heat source. It is simple to determine the input energy needed mathematically using steam tables or software, or graphically using an enthalpy-entropy chart (also known as a Mollier diagram or h-s chart). Process 2-3 involves adding heat under steady pressure to a boiler.

Process 3-4: Power is produced as the dry, saturated vapour expands through a turbine. As a result, the vapour's temperature and pressure are reduced, and some condensation may result. Using the chart or tables mentioned above, it is simple to calculate the output in this method. The isentropic expansion in process 3-4.

Process 4-1: The saturated liquid is created by condensing the wet vapour at a steady pressure inside a condenser. Constant pressure heat rejection in the condenser is process 4-1.