Stagnation enthalpy

Stagnation enthalpy of a fluid at one point is the enthalpy of the fluid at that point at a stagnation point. It represents the enthalpy of a fluid when it is brought to rest from velocity ${\displaystyle V}$ isentropically.[1] When the potential energy of the fluid is negligible, the stagnation enthalpy represents the total energy of a flowing fluid stream per unit mass.[2]

Stagnation enthalpy is the sum of the enthalpy associated with the temperature at each point plus the enthalpy associated with the dynamic pressure at each point.

${\displaystyle h_{0}=h+{\frac {V^{2}}{2}}}$

Static and stagnation states in a fluid.

where ${\displaystyle h}$ is enthalpy, and ${\displaystyle V}$ is velocity. Suffix ‘0’ denotes stagnation condition.[1][3]

Stagnation enthalpy has units of energy per unit mass, such that if enthalpy is thought of as the energy associated with the temperature plus the energy associated with the pressure, the stagnation enthalpy adds a term associated with the kinetic energy of the fluid mass.[2]

See also

• Stagnation pressure
• Stagnation temperature
• Rothalpy

References

1. Van Wylen, G.J. and Sonntag, R.E. (1976) Fundamentals of Classical Thermodynamics, section 14.1 (SI Version 2^e), John Wiley & Sons, Inc., New York
2. Çengel, Yunus A. (7 January 2014). Thermodynamics : an engineering approach. Boles, Michael A. (Eighth ed.). New York. ISBN 978-0-07-339817-4. OCLC 869741544.
3. Moran, Michael J. Fundamentals of engineering thermodynamics. Shapiro, Howard N., Boettner, Daisie D., Bailey, Margaret B. (7th ed.). [Hoboken, N.J.?]. ISBN 978-0-470-91768-8. OCLC 694944253.

External links

http://ocw.mit.edu/ans7870/16/16.unified/thermoF03/chapter_6.htm