Although technological progress is very fast, it is common to see situations where today's plants use principles that were discovered in past centuries. For example, the Rankine cycle, which was invented in the 19th century, is still used in steam turbines today.
Great inventor
The Rankine cycle was discovered by a Scottish physicist and engineer who lived and worked in the century before last. The invention was named after this great scientist, who was also one of the founders of technical thermodynamics.
Rankine William John was born in 1820 in the city of Edinburgh, where he studied for three years at the institute. However, the scientist failed to complete this institution due to the difficult financial situation. But this did not prevent the gifted physicist from making a number of useful discoveries. Thus, in 1849, he obtained equations in thermodynamics describing the relationship between mechanical energy and heat. He also carried out the construction of the theory of the steam engine and developed the basic principles that formed the basis for the operation of this unit. These provisions constitute the processnamed after the scientist, the Rankine cycle.
Highlights
This cycle is a theoretical expression of the work of thermodynamic processes occurring during the operation of steam power plants in the repetition mode. We can distinguish the following basic operations included in this cycle:
- liquid evaporates at high pressure;
- water molecules in the gaseous state expand;
- moist steam condenses on the walls of the vessel;
- fluid pressure increases (returns to original value).
It can be noted that the thermal efficiency for this cycle is directly proportional to the initial temperature. Also, the efficiency of this process depends on the pressure values and the thermal state index at the starting position and at the exit.
Steam turbine
This unit is a heat engine that generates electricity. The main components of this installation can be represented in the following list:
- moving part, which consists of a rotor and blades attached to it;
- stationary element with parts such as stator and nozzles.
The operation of the plant can be described as follows. Water in a gaseous state at high temperature and pressure is supplied to the turbine nozzles. Here, at supersonic speed, the potential energy of the steam is converted into kinetic energy, and particles are set in motionpair. This, in turn, creates a gaseous flow that acts on the turbine blades. The rotation of these elements causes the rotor to move, as a result of which electricity is generated. Next, the vapor condenses, and it settles in a special chilled water receiver, from where the liquid is again forced into the heat exchanger. Thus, the operations are repeated, that is, the Rankine cycle is carried out.
This principle is used in installations at nuclear power plants, it is also used in the operation of autonomous turbine installations for the production of electricity. This scheme is by far the most efficient and economical. Rankine-based plants are distributed all over the world.
