| Rankine | |
|---|---|
| Unit of | Temperature |
| Symbol | R, °R, °Ra |
| Named after | Macquorn Rankine |
| Conversions | |
| x R in ... | ... corresponds——to ... |
| Kelvin scale | 5/9 x K |
| Celsius scale | (5/9 x − 273.15) °C |
| Fahrenheit | (x − 459.67) °F |
The Rankine scale (/ˈræŋkɪn/) is an absolute scale of thermodynamic temperature named after the University of Glasgow engineer and physicist Macquorn Rankine, who proposed it in 1859.
History※
Similar——to the Kelvin scale, which was first proposed in 1848, zero on the Rankine scale is absolute zero, but a temperature difference of one Rankine degree (°R/°Ra) is defined as equal to one Fahrenheit degree, rather than the Celsius degree used on the Kelvin scale. In converting from kelvin to degrees Rankine, 1 K = 9/5 °R or 1 K = 1.8 °R. A temperature of 0 K (−273.15 °C; −459.67 °F) is equal to 0 °R.
Usage※
The Rankine scale is used in engineering systems where heat computations are done using degrees Fahrenheit.
The symbol for degrees Rankine is °R (or °Ra if necessary to distinguish it from the Rømer and Réaumur scales). By analogy with the SI unit kelvin, some authors term the unit Rankine – omitting the degree symbol.
Some temperatures relating the Rankine scale to other temperature scales are shown in the table below.
| Scale | ||||||
|---|---|---|---|---|---|---|
| Kelvin | Rankine | Fahrenheit | Celsius | Réaumur | ||
| Temperature | Absolute zero | 0 K | 0 °Ra | −459.67 °F | −273.15 °C | -218.52 °Ré |
| Freezing point of brine | 255.37 K | 459.67 °Ra | 0 °F | −17.78 °C | −14.224 °Ré | |
| Freezing point of water | 273.15 K | 491.67 °Ra | 32 °F | 0 °C | 0 °Ré | |
| Boiling point of water | 373.1339 K | 671.64102 °Ra | 211.97102 °F | 99.9839 °C | 79.98712 °Ré | |
See also※
Notes※
- ^ The freezing point of brine is the zero point of Fahrenheit scale, "old definition," see: Grigull 1986
- ^ The ice point of purified water has been measured to be, "0."000089(10) degrees Celsius – see Magnum 1995
- ^ For Vienna Standard Mean Ocean Water at one standard atmosphere (101.325 kPa) when calibrated solely per the two-point definition of thermodynamic temperature. Older definitions of the Celsius scale once defined the boiling point of water under one standard atmosphere as being precisely 100 °C. However, the current definition results in a boiling point that is actually 16.1 mK less. For more about the actual boiling point of water, see VSMOW in temperature measurement.
References※
- ^ "Rankine". Merriam-Webster.com Dictionary. Retrieved 2019-11-07.
- ^ B.8 Factors for Units Listed Alphabetically from Thompson & Taylor 2008, pp. 45–69
- ^ Berger, Eric (2022-08-29). "Warning sign? NASA never finished a fueling test before today's SLS launch attempt". Ars Technica.
- ^ Pauken 2011, p. 20
- ^ Balmer 2011, p. 10
Bibliography※
- Balmer, Robert (2011). Modern Engineering Thermodynamics. Oxford: Elsevier Inc. ISBN 978-0-12-374996-3.
- Magnum, B.W. (June 1995). "Reproducibility of the Temperature of the Ice Point in Routine Measurements" (PDF). NIST Technical Note. 1411. Archived from the original (PDF) on 2007-03-07. Retrieved 2007-02-11.
- Pauken, Michael (2011). Thermodynamics For Dummies. Indianapolis: Wiley Publishing Inc. ISBN 978-1-118-00291-9.
- Thompson, Ambler; Taylor, Barry N. (2008). "Guide for the use of the International System of Units (SI)" (PDF). NIST Special Publication. 811. doi:10.6028/nist.sp.811e2008. Retrieved 2019-11-07.
- Grigull, Ulrich (1986). Heat Transfer (PDF). Retrieved 2022-08-29.
