William Rankine
William John Macquorn Rankine was a prominent Scottish engineer and physicist, recognized as one of the foundational figures in the field of thermodynamics alongside contemporaries like Rudolf Clausius and Lord Kelvin. His most significant contributions include the comprehensive theory of heat engines and the development of engineering manuals that were widely utilized throughout the 19th century. Rankine's educational journey began with home schooling, followed by attendance at the High School of Glasgow and the University of Edinburgh, where he worked under influential mentors. He was particularly focused on improving railway engineering, introducing more accurate methods for laying curved rails using advanced surveying tools.
Rankine's fascination with heat led him to explore the mechanics of heat engines, including the steam engine. His key achievements include establishing the relationship between temperature and saturated vapor pressure and calculating the efficiency of heat engines, which he linked to the operational temperatures of these engines. Although he initially critiqued James Clerk Maxwell's theories, Rankine ultimately recognized their validity. Additionally, he made notable advancements in understanding metal fatigue in railway axles, laying groundwork for future studies in materials science. Rankine’s legacy continues to influence modern engineering and physics, particularly in energy-related disciplines.
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William Rankine
Dates: 1820–1872.
Summary: One of the originators of the laws of therodynamics, William Rankine is best known for his complete theory of heat engines.
William John Macquorn Rankine was a Scottish engineer and physicist who, along with Rudolf Clausius and Lord Kelvin (William Thomson), was one of the fathers of thermodynamics. Rankine’s best-known work was his complete theory of heat engines, and his engineering manuals continued to be used for most of the 19th century.
Initially educated at home, Rankine later attended the High School of Glasgow, the Military and Naval Academy, and the University of Edinburgh, which he began attending at age 16, working under James David Forbes, who was also mentor to physicist and mathematician James Clerk Maxwell.
During Rankine’s time, there was a continual problem in railway engineering in putting down curved rails, and Rankine’s method was significantly more accurate and efficient than preceding methodologies, making use of the recently developed theodolite, a precision surveying instrument used for measuring angles in vertical and horizontal planes. From early in his career, Rankine was interested in representing heat mathematically, but in his university years, he suffered from the dearth of experimental data from which to extrapolate. His interest in heat soon turned into an interest in heat engine mechanics, the mechanics of any engine that converts thermal energy into mechanical work, which in Rankine’s time included the steam engine and today also includes the internal combustion engine, among many other types. In 1849, Rankine successfully determined the relationship between temperature and saturated vapor pressure. He soon moved on to establish relationships between the temperature, pressure, and density of gases, and he predicted the counterintuitive conclusion that saturated steam has a negative apparent specific heat.
Soon Rankine had succeeded at calculating the efficiency of heat engines, and he extrapolated from his experimental data that the maximum efficiency of such an engine is a function of the temperatures between which it operates (the thermodynamic function). These results were reformulated and rephrased several times and were used to support an energy-centric formulation of dynamics, which described dynamics in terms of energy and energy transformations rather than motion and force: the science of energetics. For a time, Rankine was a vocal critic of James Clerk Maxwell’s theories of heat, because they were incompatible with some of his own models, but in 1869 he eventually admitted the validity of Maxwell’s equations.
Rankine’s best successes were in working toward practical results, analyzing properties of gases, vapors, and steam to achieve more efficient heat engines. He was also among the first to understand the fatigue failure of railway axles; he was able to show how they developed from brittle cracks and described the process now called metal fatigue.
Bibliography
Karwatka, Dennis. “William Rankine and Engineering Education.” Tech Directions 69, no. 3 (October 2009).
Lewis, Christopher J. T. Heat and Thermodynamics. Westport, CT: Greenwood, 2007.
Liszka, John. “Are You Sure, Mr. Carnot? A Re-examination of the Thermodynamic Principles as Formulated by Nicolas Carnot and William Rankine Over One Hundred Years Ago Might Lead to Greater Efficiency in Electrical Power Generating Stations, Together With Reduced Emissions.” Engineering Digest 38, no. 3 (June 1992).
Muller, Ingo. A History of Thermodynamics. New York: Springer, 2010.
Raman, V. V. “William John Macquorn Rankine (1820–1872).” Journal of Chemical Education 50, no. 4 (1973).
Sutherland, H. B. “Professor William John Macquorn Rankine.” Proceedings of the Institution of Civil Engineers Civil Engineering 132, no. 4 (1999).