Rankine, William John Macquorn (1820–1872)

Scottish engineer and physicist who was one of the founders of the science of thermodynamics, especially in reference to the theory of steam engines.

Rankine was born in Edinburgh and trained as a civil engineer. From 1855 he was professor at Glasgow. In 1849 he delivered two papers on the subject of heat, and in 1849 he showed the further modifications required to French physicist Sadi Carnot's theory of thermodynamics. In A Manual of the Steam Engine and other Prime Movers (1859), Rankine described a thermodynamic cycle of events (the Rankine cycle), which came to be used as a standard for the performance of steam-power installations where a considerable vapour provides the working fluid. Rankine here explained how a liquid in the boiler vaporized by the addition of heat converts part of this energy into mechanical energy when the vapour expands in an engine. As the exhaust vapour is condensed by a cooling medium such as water, heat is lost from the cycle. The condensed liquid is pumped back into the boiler.